Babe Bee type engine with "horseshoe" type Delrin backplate and brass needle valve. The horseshoe backplate had additional mounting holes drilled in the plate allowed fitting to after market and kit aircraft. Various shapes and colours were produced depending on the model they were fitted to. Some had dual bypass port cylinders while others had single, it depended on the airplane. e.g. Sopwith Camel, Fokker DVII, ME-109, Super Stunter, PT-19 Trainer and others produced in the mid 1970s.