Spring used on the shooter rod outside of the pinball cabinet.  At 0.75" long, this barrel spring is a little shorter than the longer 0.875" barrel spring.  This spring is used on all Data East, Sega, and Stern games as well as many Gottlieb, Williams, and Bally games.

Chrome finish.

Williams/Bally reference #10-149.

Data East/Sega/Stern reference #266-5010-00.