Ryobi ZRP310 ONE Plus 18V Cordless Power Caulk and Adhesive Gun (Bare Tool) (Certified Refurbished) All metal manual plunger rod with hook-end lets you quickly change out tubes Center balanced handle with over-mold for increased user comfort and on-board puncture tool Over 500 lbs. of push force to handle the higher viscosity materials Switch lock helps prevent accidental start-ups and Variable speed selector to adjust discharge rate