The Fixed Diameter Hole Opener is made of tough heat treated alloy steel for maximum strength. Cutter arms, equipped with removable cutter, are hardfaced and welded on body. Cutters are available in three types: type SM for soft to medium formation, type MH for medium to hard formation and type XH for hard formation. The hole openers have three or six jet tubes with replaceable nozzles, so that jet streams quickly clean the enlarged hole.