diff --git a/src/number.rs b/src/number.rs
index 08faf94..d669a34 100644
--- a/src/number.rs
+++ b/src/number.rs
@@ -900,8 +900,6 @@ float_number_trait_impl!(Number for f64, -1.7976931348623157e+308f64,
                                           1.7976931348623157e+308f64,
                                           fmin, fmax);
 
-#[cfg(target_pointer_width = "8")]
-int_number_trait_impl!(Number for usize, 0usize, 255usize);
 #[cfg(target_pointer_width = "16")]
 int_number_trait_impl!(Number for usize, 0usize, 65535usize);
 #[cfg(target_pointer_width = "32")]
@@ -909,8 +907,6 @@ int_number_trait_impl!(Number for usize, 0usize, 4294967295usize);
 #[cfg(target_pointer_width = "64")]
 int_number_trait_impl!(Number for usize, 0usize, 18446744073709551615usize);
 
-#[cfg(target_pointer_width = "8")]
-int_number_trait_impl!(Number for isize, -128isize, 127isize);
 #[cfg(target_pointer_width = "16")]
 int_number_trait_impl!(Number for isize, -32768isize, 32767isize);
 #[cfg(target_pointer_width = "32")]