Flawless workmanship and easy installation of the holder by means of two adhesive pads. With me several PowerCubes already hanging on vertical surfaces of furniture. The adhesive pads are far strong enough to hold the resulting during insertion of plugs shear forces when they are with one hand - inserting - without counter-holding. But for safety I always use two hands when plugging of plugs. I've noticed that you have to spend a lot of different force to insert the plug contacts through the protected openings.