diff --git a/segpy/revisions.py b/segpy/revisions.py
index c6fee03..c06fc36 100644
--- a/segpy/revisions.py
+++ b/segpy/revisions.py
@@ -1,12 +1,20 @@
-SEGY_REVISION_0 = 0
-SEGY_REVISION_1 = 1
+"""SEG Y Revision numbers
 
-VARIANTS = {SEGY_REVISION_0: SEGY_REVISION_0,
-            SEGY_REVISION_1: SEGY_REVISION_1,
-            0: SEGY_REVISION_0,
-            1: SEGY_REVISION_1,
-            100: SEGY_REVISION_1,
-            256: SEGY_REVISION_1}
+From the specification:
+
+    SEG Y Format Revision Number. This is a 16-bit unsigned value with a Q- point between the first and second bytes.
+    Thus for SEG Y Revision 1.0, as defined in this document, this will be recorded as 0100 in base 16.
+"""
+
+
+SEGY_REVISION_0 = 0x0000
+SEGY_REVISION_1 = 0x0100
+
+VARIANTS = {
+    SEGY_REVISION_0: SEGY_REVISION_0,  # Ensure that SEGY_REVISION_0 maps to itself
+    SEGY_REVISION_1: SEGY_REVISION_1,  # Ensure that SEGY_REVISION_1 maps to itself
+    1: SEGY_REVISION_1,                # Common, but erroneous, decimal one
+    100: SEGY_REVISION_1}              # Common, but erroneous, decimal one-hundred
 
 
 class SegYRevisionError(Exception):