Factory Reconditioned Ryobi ZRRY10520 46 cc Gas Powered 20 in. Chain Saw Manufacturer Refurbished RYOBI RY10520 20" 46cc Gas Powered 2-Cycle Chain Saw 50:1 Gas to Oil ratio, which is 2.6oz of oil to 1 gallon of gas. Do NOT use E85 gas Pro Grade Chain -- Offers Aggressive Cutting Action 20" Bar and Chain -- Cuts Logs up to 40" in Diameter Inertia Activated Chain Brake -- Stops Chain Automatically