The swiveling top support fits Brodit holders where the plate that attaches the tilt swivel to the holder is 42x50mm. Perfect if you have a holder for a rugged PDA mounted in a rougher environment where it is at risk of falling out. It is easy to attach the top support onto the holder, and adjust the height to fit with your device. To make sure the top support works with your holder and device, measure the distance from the top edge of the tilt swivel to the top of the device when placed in the holder, the top support fits if the distance is between 85 mm to 100 mm.