Turtle Back Gate Closer gently closes both small and large gates up to 125 lbs. TB100 has adjustable closing speed. It can be install on top, middle or bottom of gates. The gate closer is recommended for pool, garden and barrier gates. TB100 can be used on lightweight (non fire-rated) doors, works best on gates with in-line/flush hinges. To retain product warranty & restrict gate opening angle, a gate stop must be installed. The LockeyUSA Turtle Back TB100 Hydraulic Gate closer must mount on the hinge side/pull side of the gate in order to push the gate closed. The TB100 works best if the gate has in-line/flush hinges flush with the gate post with 1" or less gap.