550 Snowmobile Cylinder (3085936) from 2003 Trail Touring.. these are “Steel Sleeve” cylinders.. 73mm / Standard BoreSpecific to many 550 fan cooled models from 1999 – 2004 that have a “decompression” hole in exhaust side of the cylinder wall… will fit other 550 fan models up to 2006 that have “steel sleeve” cylinders w/o the hole…Take-off Cylinders from good running sleds with frame damage… NO damage or scoring.. still with-in factory tolerances..SHIPPING: UPS or FedEXRELATED PARTS.. We have Heads, Cranks, Cases, Reeds and more.. Just email us if you need anything else..