I didn't even know there was such a thing. These are going on my next house. On 2/3/2017 9:36 AM, Steve Hammatt, Mount Vernon WA USA wrote: > My lifts are LiftMaster Jackshaft > design (love the space saving and very quiet operation. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus