This standard type of gear pack is well known and accepted within the trade. Our Retractable Lifting Gear cover weights from 100lbs (45kg) up to 350lbs (158kg) and have multi position spring location to give great flexibility and improved door balance. Ideal for use on automatic electric operation. Maximum obstruction in front of garage door is 1140mm (4ft) on 2134mm (7ft) height door. CHECK OPENING HEIGHT & WEIGHT BEFORE ORDERING ANY RETRACTABLE GEAR PACK