Yup. It's old enough not to be listed on OS' website. What is it used for? Well, any .60 - 1.20 size 3D, sport or scale plane. Looks like a nice engine. Good luck finding parts for it though. I would imagine the piston and sleeve, connecting rod, bearrings and crankshaft are quite different from the FX version sold today. If it's brand new, and broken correctly, you may never have to replace any parts. It's probably a bit heavier than the ones sold now, but it should put out close to what the new ones do (between 2.5 and 2.8 BHP). Keep in mind though, a brand new one only costs $210 with warrantee.