How to tell rather you have a type 56 or a type 57 cash drawer insert for the SAM4s SPS-500 series register. Older SPS-500 series were released with the Type 56 Insert. Please see examples below
The first place to check and see what type of drawer you have is to check the label on the left hand side if the front of the outside of the drawer. See Examples below
You can order the correct cash drawer insert for the SAM4s cash registers here