Its easy to do the insert, just make a little hole in the other one with a screwdriver and hook it out, the other one just presses in, after reading this i decided to wear mine, mine is ok for swimming and it has no screw down criwn, as long as the rubber o ring is tight on the case tube its ok, the original didn't have a screw in crown either as rolex exclusively held the patent back then so other brands weren't able to use screw down crowns. Sent from my LYA-L09 using Tapatalk