diff --git a/examples/matrixkeypad_simpletest.py b/examples/matrixkeypad_simpletest.py
index d3210ab..f12c63c 100644
--- a/examples/matrixkeypad_simpletest.py
+++ b/examples/matrixkeypad_simpletest.py
@@ -3,9 +3,13 @@
 import board
 import adafruit_matrixkeypad
 
-# Classic 3x4 matrix keypad
+# Membrane 3x4 matrix keypad - https://www.adafruit.com/product/419
 cols = [digitalio.DigitalInOut(x) for x in (board.D9, board.D6, board.D5)]
 rows = [digitalio.DigitalInOut(x) for x in (board.D13, board.D12, board.D11, board.D10)]
+# 3x4 matrix keypad - Rows and columns are mixed up for https://www.adafruit.com/product/3845
+# Use the same wiring as in the guide with the following setup lines:
+# cols = [digitalio.DigitalInOut(x) for x in (board.D11, board.D13, board.D9)]
+# rows = [digitalio.DigitalInOut(x) for x in (board.D12, board.D5, board.D6, board.D10)]
 keys = ((1, 2, 3),
         (4, 5, 6),
         (7, 8, 9),