TELCO CO2 MODEL AIRPLANE ENGINE. I DO NOT KNOW ANYTHING ABOUT THESE ENGINES. THEY CAME ALONG WITH SOME OTHER STUFF I BOUGHT. THEY DID COME WITH AN INVENTORY LIST WITH BRIEF DESCRIPTION BUT I DO NOT KNOW HOW ACCURATE IT IS . SO ANY IFORMATION ABOUT CONDITION IS FROM THIS INVENTORY LIST. I AM SELLING "AS IS" NO RETURNS, SO PLEASE ASK ANY QUESTIONS YOU HAVE. THE INVENTORY LIST SAYS IT HAS ONLY BEEN RUN ONE TIME AND I SEE NOTHING OUT OF THE ORDINARY WITH THIS ENGINE. I SHIP ALL ITEMS SIGNATURE REQUIRED, IN NEW CLEAN BOX, BUBBLE WRAP, AND PEANUTS. I DESCRIBE ALL ITEMS TO THE BEST OF MY ABILITY. IF YOU HAVE ANY QUESTIONS I WILL TRY TO ANSWER THEM. THANK YOU FOR LOOKING.