The old ones with the metal paddle work great. this stupid PLASTIC CHEESE is will barely stay set for 3 seconds. Yes, there is a firm and sensitive side...but believe me, it should be "retardedly sensitive" and "doesn't even f-king work" sides.DO NOT BUY THESE!!! trust me, trust me, trust me. Buy the old school Victor traps with the Metal trigger..I just threw these away. useless.