diff --git a/split_reel.scad b/split_reel.scad
index d3a322e..da252f6 100644
--- a/split_reel.scad
+++ b/split_reel.scad
@@ -118,7 +118,7 @@ module split_reel_16mm_B ( length = 120) {
 module split_reel_super8_A ( length = 120) { 
     BaseH = 4;
     NotchH = 2;
-    NotchW = 19;
+    NotchW = 21;
     
     difference () {
         union () {