I order 2 of http://www.horizonhobby.com/Products...ProdID=HAN3001 for my Alpha 60 with the Evolution .61 engine. However I received 24, so I hope to be able to use them on most of my future engines too. What O.S. plug do they compare to? They don't have a description, so i don't know if they are medium or hot plugs, or anything else. Can they be used in most O.S. Engines? What about 4-stroke? Im just wondering if I limited to.

Thanks