Quoted from RobKnapp:First off Williams/Bally/Midway are called Jet Bumpers. Sega/Data East/ Stern are called POP bumpers. Worst Jet bumpers in my collection are on TOTAN. There is a left orbit shot to feed the Jet Bumpers. A switch makes a post shoot up to divert the pinball into the Jets but 99% of the time the pinball fly's right buy. Best POP Bumper action in my collection is the POPs on STERN's The X-MEN L.E. When in STORM mode the POPs trigger the shaker motor so well the floor shakes.
When Bally was Bally and Williams was Williams; Bally had Thumper Bumpers, Williams had Jet Bumpers and Gogtlieb had Pop Bumpers. Not suer about Chicago Coin or Stern Electronics. May have just been "Bumpers".