diff --git a/src/hyperfine/app.rs b/src/hyperfine/app.rs
index 5863553..9e2aa9c 100644
--- a/src/hyperfine/app.rs
+++ b/src/hyperfine/app.rs
@@ -129,10 +129,9 @@ fn build_app() -> App<'static, 'static> {
                 .long("time-unit")
                 .short("u")
                 .takes_value(true)
-                .value_name("millisecond|second")
+                .value_name("UNIT")
                 .possible_values(&["millisecond", "second"])
-                .help( "Set the time unit used for CLI output and Markdown export.",
-                ),
+                .help("Set the time unit used. Possible values: millisecond, second."),
         )
         .arg(
             Arg::with_name("export-csv")
diff --git a/src/hyperfine/benchmark.rs b/src/hyperfine/benchmark.rs
index 6e89c53..3be7bb6 100644
--- a/src/hyperfine/benchmark.rs
+++ b/src/hyperfine/benchmark.rs
@@ -11,8 +11,8 @@ use hyperfine::outlier_detection::{modified_zscores, OUTLIER_THRESHOLD};
 use hyperfine::shell::execute_and_time;
 use hyperfine::timer::wallclocktimer::WallClockTimer;
 use hyperfine::timer::{TimerStart, TimerStop};
-use hyperfine::types::{BenchmarkResult, Command};
-use hyperfine::types::{CmdFailureAction, HyperfineOptions, OutputStyleOption, Second};
+use hyperfine::types::{BenchmarkResult, Command, CmdFailureAction, HyperfineOptions, OutputStyleOption};
+use hyperfine::units::Second;
 use hyperfine::warnings::Warnings;
 
 /// Results from timing a single shell command
diff --git a/src/hyperfine/export/csv.rs b/src/hyperfine/export/csv.rs
index 7be8b46..57c0bef 100644
--- a/src/hyperfine/export/csv.rs
+++ b/src/hyperfine/export/csv.rs
@@ -1,6 +1,7 @@
 use super::Exporter;
 
-use hyperfine::types::{BenchmarkResult, Unit};
+use hyperfine::types::BenchmarkResult;
+use hyperfine::units::Unit;
 
 use std::io::{Error, ErrorKind, Result};
 
diff --git a/src/hyperfine/export/json.rs b/src/hyperfine/export/json.rs
index 4e6e311..62a3f50 100644
--- a/src/hyperfine/export/json.rs
+++ b/src/hyperfine/export/json.rs
@@ -1,5 +1,6 @@
 use super::Exporter;
-use hyperfine::types::{BenchmarkResult, Unit};
+use hyperfine::types::BenchmarkResult;
+use hyperfine::units::Unit;
 
 use std::io::{Error, ErrorKind, Result};
 
diff --git a/src/hyperfine/export/markdown.rs b/src/hyperfine/export/markdown.rs
index 00b22c0..d008c5a 100644
--- a/src/hyperfine/export/markdown.rs
+++ b/src/hyperfine/export/markdown.rs
@@ -1,7 +1,8 @@
 use super::Exporter;
 
 use hyperfine::format::format_duration_value;
-use hyperfine::types::{BenchmarkResult, Unit};
+use hyperfine::types::BenchmarkResult;
+use hyperfine::units::Unit;
 
 use std::io::Result;
 
@@ -10,9 +11,9 @@ pub struct MarkdownExporter {}
 
 impl Exporter for MarkdownExporter {
     fn serialize(&self, results: &Vec<BenchmarkResult>, unit: Option<Unit>) -> Result<Vec<u8>> {
-        let unit = if unit.is_some() {
+        let unit = if let Some(unit) = unit {
             // Use the given unit for all entries.
-            unit.unwrap()
+            unit
         } else if let Some(first_result) = results.first() {
             // Use the first BenchmarkResult entry to determine the unit for all entries.
             format_duration_value(first_result.mean, None).1
diff --git a/src/hyperfine/export/mod.rs b/src/hyperfine/export/mod.rs
index 852c4fd..b7ec0c9 100644
--- a/src/hyperfine/export/mod.rs
+++ b/src/hyperfine/export/mod.rs
@@ -9,7 +9,8 @@ use self::markdown::MarkdownExporter;
 use std::fs::File;
 use std::io::{Result, Write};
 
-use hyperfine::types::{BenchmarkResult, Unit};
+use hyperfine::types::BenchmarkResult;
+use hyperfine::units::Unit;
 
 /// The desired form of exporter to use for a given file.
 #[derive(Clone)]
diff --git a/src/hyperfine/format.rs b/src/hyperfine/format.rs
index 7f7471c..08f0c61 100644
--- a/src/hyperfine/format.rs
+++ b/src/hyperfine/format.rs
@@ -1,4 +1,4 @@
-use hyperfine::types::{Second, Unit};
+use hyperfine::units::{Second, Unit};
 
 /// Format the given duration as a string. The output-unit can be enforced by setting `unit` to
 /// `Some(target_unit)`. If `unit` is `None`, it will be determined automatically.
diff --git a/src/hyperfine/internal.rs b/src/hyperfine/internal.rs
index 24f766c..51ea152 100644
--- a/src/hyperfine/internal.rs
+++ b/src/hyperfine/internal.rs
@@ -1,7 +1,8 @@
 use colored::*;
 use indicatif::{ProgressBar, ProgressStyle};
 
-use hyperfine::types::{BenchmarkResult, OutputStyleOption, Second};
+use hyperfine::types::{BenchmarkResult, OutputStyleOption};
+use hyperfine::units::Second;
 
 use std::cmp::Ordering;
 use std::iter::Iterator;
diff --git a/src/hyperfine/mod.rs b/src/hyperfine/mod.rs
index 0c7f34a..e6af195 100644
--- a/src/hyperfine/mod.rs
+++ b/src/hyperfine/mod.rs
@@ -8,4 +8,5 @@ pub mod outlier_detection;
 pub mod shell;
 pub mod timer;
 pub mod types;
+pub mod units;
 pub mod warnings;
diff --git a/src/hyperfine/timer/internal.rs b/src/hyperfine/timer/internal.rs
index 04cc2a7..49ef3ce 100644
--- a/src/hyperfine/timer/internal.rs
+++ b/src/hyperfine/timer/internal.rs
@@ -1,4 +1,4 @@
-use hyperfine::types::Second;
+use hyperfine::units::Second;
 
 #[derive(Debug, Copy, Clone)]
 pub struct CPUTimes {
diff --git a/src/hyperfine/timer/unix_timer.rs b/src/hyperfine/timer/unix_timer.rs
index 33457c2..8d940dd 100644
--- a/src/hyperfine/timer/unix_timer.rs
+++ b/src/hyperfine/timer/unix_timer.rs
@@ -2,7 +2,7 @@
 
 use super::internal::{CPUInterval, CPUTimes};
 use hyperfine::timer::{TimerStart, TimerStop};
-use hyperfine::types::Second;
+use hyperfine::units::Second;
 
 use std::mem;
 use std::process::Child;
diff --git a/src/hyperfine/timer/wallclocktimer.rs b/src/hyperfine/timer/wallclocktimer.rs
index 3780ecb..b28a24e 100644
--- a/src/hyperfine/timer/wallclocktimer.rs
+++ b/src/hyperfine/timer/wallclocktimer.rs
@@ -2,7 +2,7 @@ use std::process::Child;
 use std::time::Instant;
 
 use hyperfine::timer::{TimerStart, TimerStop};
-use hyperfine::types::Second;
+use hyperfine::units::Second;
 
 pub struct WallClockTimer {
     start: Instant,
diff --git a/src/hyperfine/timer/windows_timer.rs b/src/hyperfine/timer/windows_timer.rs
index 512600e..4471e8d 100644
--- a/src/hyperfine/timer/windows_timer.rs
+++ b/src/hyperfine/timer/windows_timer.rs
@@ -1,8 +1,8 @@
 #![cfg(windows)]
 
 use super::internal::CPUTimes;
-use hyperfine::types::Second;
 use hyperfine::timer::{TimerStart, TimerStop};
+use hyperfine::units::Second;
 
 use winapi::um::processthreadsapi::GetProcessTimes;
 use winapi::um::winnt::HANDLE;
diff --git a/src/hyperfine/types.rs b/src/hyperfine/types.rs
index dd2547d..1568a5e 100644
--- a/src/hyperfine/types.rs
+++ b/src/hyperfine/types.rs
@@ -1,40 +1,14 @@
 /// This module contains common internal types.
 use std::fmt;
 
+use hyperfine::units::{Second, Unit};
+
 #[cfg(not(windows))]
 pub const DEFAULT_SHELL: &str = "sh";
 
 #[cfg(windows)]
 pub const DEFAULT_SHELL: &str = "cmd.exe";
 
-/// Type alias for unit of time
-pub type Second = f64;
-
-/// Supported time units
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum Unit {
-    Second,
-    MilliSecond,
-}
-
-impl Unit {
-    /// The abbreviation of the Unit.
-    pub fn short_name(&self) -> String {
-        match *self {
-            Unit::Second => String::from("s"),
-            Unit::MilliSecond => String::from("ms"),
-        }
-    }
-
-    /// Returns the Second value formatted for the Unit.
-    pub fn format(&self, value: Second) -> String {
-        match *self {
-            Unit::Second => format!("{:.3}", value),
-            Unit::MilliSecond => format!("{:.1}", value * 1e3),
-        }
-    }
-}
-
 /// A command that should be benchmarked.
 #[derive(Debug, Clone)]
 pub struct Command<'a> {
@@ -221,17 +195,3 @@ impl BenchmarkResult {
         }
     }
 }
-
-#[test]
-fn test_unit_short_name() {
-    assert_eq!("s", Unit::Second.short_name());
-    assert_eq!("ms", Unit::MilliSecond.short_name());
-}
-
-// Note - the values are rounded when formatted.
-#[test]
-fn test_unit_format() {
-    let value: Second = 123.456789;
-    assert_eq!("123.457", Unit::Second.format(value));
-    assert_eq!("123456.8", Unit::MilliSecond.format(value));
-}
diff --git a/src/hyperfine/units.rs b/src/hyperfine/units.rs
new file mode 100644
index 0000000..7da1843
--- /dev/null
+++ b/src/hyperfine/units.rs
@@ -0,0 +1,43 @@
+/// This module contains common units.
+
+/// Type alias for unit of time
+pub type Second = f64;
+
+/// Supported time units
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Unit {
+    Second,
+    MilliSecond,
+}
+
+impl Unit {
+    /// The abbreviation of the Unit.
+    pub fn short_name(&self) -> String {
+        match *self {
+            Unit::Second => String::from("s"),
+            Unit::MilliSecond => String::from("ms"),
+        }
+    }
+
+    /// Returns the Second value formatted for the Unit.
+    pub fn format(&self, value: Second) -> String {
+        match *self {
+            Unit::Second => format!("{:.3}", value),
+            Unit::MilliSecond => format!("{:.1}", value * 1e3),
+        }
+    }
+}
+
+#[test]
+fn test_unit_short_name() {
+    assert_eq!("s", Unit::Second.short_name());
+    assert_eq!("ms", Unit::MilliSecond.short_name());
+}
+
+// Note - the values are rounded when formatted.
+#[test]
+fn test_unit_format() {
+    let value: Second = 123.456789;
+    assert_eq!("123.457", Unit::Second.format(value));
+    assert_eq!("123456.8", Unit::MilliSecond.format(value));
+}
diff --git a/src/hyperfine/warnings.rs b/src/hyperfine/warnings.rs
index 7032ed4..d14df60 100644
--- a/src/hyperfine/warnings.rs
+++ b/src/hyperfine/warnings.rs
@@ -2,7 +2,7 @@ use std::fmt;
 
 use hyperfine::format::format_duration;
 use hyperfine::internal::MIN_EXECUTION_TIME;
-use hyperfine::types::Second;
+use hyperfine::units::Second;
 
 /// A list of all possible warnings
 pub enum Warnings {
diff --git a/src/main.rs b/src/main.rs
index 7940e6b..9a0c49c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -46,8 +46,9 @@ use hyperfine::error::{OptionsError, ParameterScanError};
 use hyperfine::export::{ExportManager, ExportType};
 use hyperfine::internal::write_benchmark_comparison;
 use hyperfine::types::{
-    BenchmarkResult, Unit, CmdFailureAction, Command, HyperfineOptions, OutputStyleOption,
+    BenchmarkResult, CmdFailureAction, Command, HyperfineOptions, OutputStyleOption,
 };
+use hyperfine::units::Unit;
 
 /// Print error message to stderr and terminate
 pub fn error(message: &str) -> ! {
@@ -95,9 +96,9 @@ fn main() {
     let export_manager = build_export_manager(&matches);
     let commands = build_commands(&matches);
 
-    let res = match &options {
-        &Ok(ref opts) => run(&commands, &opts),
-        &Err(ref e) => error(e.description()),
+    let res = match options {
+        Ok(ref opts) => run(&commands, &opts),
+        Err(ref e) => error(e.description()),
     };
 
     match res {