S size. Confident you'll need some force, but this is due to The point that the fast modify buckle is held in place by friction. This might be the weak point to anyone but I have found this to become of no complications for me, the sling has not skipped https://smith-wesson-m-p-15-22-ma61604.ka-blogs.com/87877732/the-greatest-guide-to-barska-compact-biometric-safe-with-biometric-access