Solid grip, no idea about the pad - KRISS USA G3 Vertical Grip Handstop with Pad

This grip is exactly what I was looking for to put on an SBR PC Charger. It has a solid handstop and plenty of grip for my average hand. I wasn't sure it would fit on the short handrail of the charger but it fit perfectly on the one and a half 6oclock mlok rails. The back of the base sticks out a little into the takedown button, but it's reachable. The only thing that boggles me about the grip is the pad insert feature. A normal streamlight switch pad doesnt even come close to fitting inside of it. I have no idea what does. What a shame since it was one of the reasons I bought it. Welp, time for double sided tape I guess.