MODEL RC TUNED ALLOY EXPANSION PIPE, I USED IT ON A 21 & HP40 ENGINE, CAN BE USED ON 21-40  ENGINE, JUST VARY THE LENGTH

LENGTH ABOUT 32 cm LONG, ABOUT 5/8" OR 16/17MM ENTRY DIAMETER

I USED THEM IN A BOAT WITH WATER COOLED JACKET, COULD BE USED AS AERO ALSO

VERY NICE QUALITY & CONDITION, I BROUGHT THEM ABOUT 40 YEARS AGO FROM AERO NAUTICAL MODELS, KENTISH TOWN, IN LONDON, COULD BE BY RIPMAX MODELS, I HONESTLY CANNOT REMEMBER OR IRVINE/ED ETC

I HAVE CLEANED IT INTERNALLY, LOOKING VERY NICE

GRAB IT WHILE YOU CAN

THANKS FOR LOOKING......