A combination kit includes an oscillating power tool and accessory. The tool includes a housing, motor, transmission to convert rotational motion to oscillating motion, output spindle, and accessory attachment mechanism. The mechanism has a first clamping face with projections, a second clamping face, and a central post. The accessory includes a working end, an opposite rear end, and a fitment adjacent the rear end. The fitment includes a generally U-shaped opening open at the rear end that receives the post, a first plurality of openings in communication with and extending radially outward from the U-shaped opening, and a second plurality of openings not in communication with and positioned radially outward from the U-shaped opening.