Picture rail slides on the first side. The hook part swings so it can be used for ceilings and walls. This product is for picture rail R only. Material: Brass. When mounted on the wall: Length 1.4 inches (35 mm) / Width 0.7 inches (17 mm); Ceiling Length 1.5 inches (39 mm) / Width 0.7 inches (17 mm); Weight capacity is 8.8 lbs (4 kg). Use with wire hooks.