Been there done that.
Works great.....if you have strong wrists!
Put one in the wifes Shield9, was hopeful that it would assist with racking the slide. It does.
But when you park some older, tired, arthritic wrists behind it...not so much.
When we put it in the gun went immediatly to a 50% FTL failure rate. When I shot it, it seemed fine. Back to her and back to 50%
Put the OEM unit back in and no issues.
So....there is that