Poulan 961880007 PO521 21 in. Gas Snow Blower NEW /Full WarrantyPoulan 961880007 PO521 21 in. Gas Snow Blower This tool is 100% BRAND NEW!! The Poulan 21-inch single stage snow thrower features a Storm Force 4-stroke 136cc engine that delivers powerful performance and effortless starting. The 21-inch auger width and 13-inch auger diameter make.