Garage Door Pusher Bumper Springs 33" (Pair) These springs were created for sectional overhead doors that require a jack-shaft opener or hit the back of the track and cause the cables to lose tension during opening. The overall length measures 33" with a 12 gauge bracket for 3/8" Bolts 26" Travel and 2" Diameter Rubber Bumper Compression is Approximately 2.5lb/in Maintains Cable Tension and mounts inside Horizontal Track These garage door pusher bumper springs are made from zinc plated steel and are sold in pairs of Two, One Left and One right spring.