Bottom and top pins that have a spooled design (can also be called “serrated”) help increase pick resistance. A spool pin is designed so that when a picking attempt occurs the pins will tilt back and forth giving the indication that the pin chamber has been successfully picked, when in all actuality it has not. Spooled pins are design to increase the amount of time required to pick a cylinder.

Language to use in key system specification:
The manufacturer’s bottom and top pin segments shall have certain pins that are spooled to resist picking attacks.