In this helpful video, UmpireHockey.com publisher Cris Maloney demonstrates how to check a stick to see whether it violates the Rule limiting a stick's box to 25 millimeters.
NOTE: Using a quarter to check the stick's bow is not acceptable. A quarter is close to the correct size but is too small. Therefore, perfectly legal sticks might be ruled as having an illegal bow if measured using a quarter. Precision cut cylinders are available from Longstreth.