S size. Positive you may need some force, but this is due to The point that the quick modify buckle is held in place by friction. This could possibly be the weak point to somebody but I have discovered this to generally be of no troubles for me, the sling https://buy-charles-daly-301-pump71491.blogminds.com/5-tips-about-kp15-lowers-you-can-use-today-31774058