Looks quality, but... - FAB Defense Tactical Horizontal Foregrip w/ 1-1/8" Flashlight Adapter

Just got the grip in the mail, and it even arrived a day early. Just installed it on my mossberg 88 maverick, and it looks, and feels great! But i just tried to insert a flashlight into the dedicated hole through the grip, and im not sure exactly how its supposed to secure the flashlight to the grip. I pressed the button on the back, and ended up just sliding the light right through the hole. Maybe its just user error though. Overall good looking grip �