diff --git a/src/lib.rs b/src/lib.rs
index 9ab2df9..736b4db 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,7 +2,9 @@
 //!
 //! https://github.com/Marc-B-Reynolds/Stand-alone-junk/blob/master/src/SFH/prns.h
 
-use std::num::Wrapping;
+#![no_std]
+
+use core::num::Wrapping;
 
 #[derive(Default)]
 pub struct Prns {