Originally Posted by Tall Pine
Installing the "small" backstrap is thought to be .........
The Gen 4 comes standard as 'small'. The 'small' is permanent. You can add
a 'medium' or 'large' backstrap on top of the factory small.
I put on my medium backstrap in about 30 seconds today. Disassemble tool included works OK. The tool is used to drift out the housing pin (and to put in the replacement pin).