These are Guillow's 2" 2-piece plastic wheels to be used on their rubber- powered planes. These can be used on a variety of craft projects. FEATURES: Black plastic 2" diameter wheels. These come in two halves and must be glued together. These can be used with any Guillows' kit or any hobby crafts that you wish. SPECS: Eight halves per package,(four total wheels) black plastic, 2" diameter. REQUIRES: CA or model airplane glue