I've been using a cheap set of suction cups when this beast is what I needed all along. I came across these at work where we use them to install aircraft windshields, which are HEAVY and awkward to get into position. These cups will be great working on sliding glass doors to lift out and repair rollers and tracks. Pump the piston until it is completely retracted, and you're locked on solid. If it starts leaking down, you'll see the piston working its way up, giving you plenty of warning before it lets go. A push button lever on the opposite side releases the piston when you're ready. The only drawback I see is that the handle is plastic. Feels strong enough but it is plastic. If it were aluminum or steel this thing would be nearly indestructible. Be sure to order extras, you'll want more than one.