I just bought another saw from ebay. I bought it cause it was listed as a pm55. But nothing on it lead me to think it. The air filter cover sticker says 55 but, nothing else does. Its right hand start, straight carry handle, no curve for the left hand starter housing, its got a larger muffler on it, not the little flat one. The fuel tank has external adjustments that look oddly familiar to me. I believe its a 6-10A. So i offered him $60.00 and he accepted. The compression release is push button type above the spark plug which is different than my 6-10 that has the integrated run stop and compression release all in one. It has no throttle lock though?? Puzzles me. Looking at some pictures on the web i see both variants. Ill find out when it gets here. Incidentally the 6-10 i have came to me with the wrong air filter cover also, which also was from a pm55!! Ironic.