These are Guillow's 1 1/2" 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 1 1/2" 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: 8 halves per package,(four total wheels) black plastic, 1 1/2 diameter. REQUIRES: CA or model airplane glue