Installation Video: Pro-GH - Continuous duty worm gear jackshaft operator with emergency chain hoist March 31, 2021 21:02 Updated Related articles Installation Video: Pro-GSD - Continuous duty worm gear horizontal sliding door operator Installation Video: Pro-HB - Continuous duty belt drive jackshaft operator with brake How- To: Install a Nice Garage Door Transmitter How-To: Nice Garage Door Interlock Switch Pro-GJ Spec Sheet