Specialty keys include tube keys, bit and barrel keys, flat steel keys, as well as antique and skeleton keys.
A skeleton key is a simple design that usually has a cylindrical shaft and a single flat rectangular piece on the end. Skeleton keys provide minimal security and are only a slight deterrent, as any key similar in size and cuts may open the lock, including many other objects that will fit in the lock.
A flat steel key is usually made from steel and other materials, and are used in warded padlocks, gym lockers, yard tractors, etc.
A bit key usually has a solid shank, and a barrel key has a hollow shank. Bit and barrel keys are usually found in vintage homes, antique furniture, and used as decorative pieces.
A tubular key has a hollow, cylindrical shaft that is much shorter and larger than most conventional keys. They include a number of grooves of varying lengths that are cut into the outer surface at the edge of the key.