diff --git a/lib/ext/render.js b/lib/ext/render.js
index b609c29..bb3fbf8 100644
--- a/lib/ext/render.js
+++ b/lib/ext/render.js
@@ -170,7 +170,7 @@ exports.requireExt = function(display, callback)
             }
 
             ext.SetPictureTransform = function(pid, matrix) {
-              var format = 'CCSLLLLLLLLLLLLL';
+              var format = 'CCSLLLLLLLLLL';
               if (matrix.length !== 9)
                 throw 'Render.SetPictureTransform: incorrect transform matrix. Must be array of 9 numbers';
               var params = [ext.majorOpcode, 28, 11, pid];