Glass knobs with die cast bases and one 17/64 inch square spindle. Used on interior latch sets. Fits square drive spindle systems common on antique and vintage door hardware sets. Warning: This door knob is made of glass. It can crack or break if banged against a wall or hit with a solid object like a hammer. Broken glass is very sharp and can seriously cut you. If door knob cracks or becomes loose, replace immediately. DO NOT let children hang from this product.