An accessory for coupling to an attachment mechanism of an oscillating power tool, the accessory comprising: a working end portion; and an opposite rear end portion configured to be coupled to a plurality of different configurations of attachment mechanisms for oscillating power tools, the rear end portion including: a generally U-shaped opening open to the rear end portion, the U-shaped opening having a central portion configured to receive a central post of a tool clamping mechanism, and a rearward portion in communication with the central portion and open to the rear end portion of the accessory; a first plurality of openings in communication with and extending radially outward from the central opening, the first plurality of openings including a first radial arm slot extending from the central portion at 90 degrees to the U-shaped opening, a second radial arm slot extending from the central portion at 180 degrees to the U-shaped opening, and a third radial arm slot extending from the central portion at 270 degrees from the U-shaped opening; and a second plurality of openings not in communication with and positioned radially outward from the central opening; characterised in that the second plurality of openings are positioned between adjacent radial arm slots in the first plurality of openings; and that the rear end portion further includes a pair of chamfers (916a, 916b) tapering outward from the U-shaped opening to the rear end portion. a working end portion; and an opposite rear end portion configured to be coupled to a plurality of different configurations of attachment mechanisms for oscillating power tools, the rear end portion including: a generally U-shaped opening open to the rear end portion, the U-shaped opening having a central portion configured to receive a central post of a tool clamping mechanism, and a rearward portion in communication with the central portion and open to the rear end portion of the accessory; a first plurality of openings in communication with and extending radially outward from the central opening, the first plurality of openings including a first radial arm slot extending from the central portion at 90 degrees to the U-shaped opening, a second radial arm slot extending from the central portion at 180 degrees to the U-shaped opening, and a third radial arm slot extending from the central portion at 270 degrees from the U-shaped opening; and a second plurality of openings not in communication with and positioned radially outward from the central opening; characterised in that the second plurality of openings are positioned between adjacent radial arm slots in the first plurality of openings; and that the rear end portion further includes a pair of chamfers (916a, 916b) tapering outward from the U-shaped opening to the rear end portion. a generally U-shaped opening open to the rear end portion, the U-shaped opening having a central portion configured to receive a central post of a tool clamping mechanism, and a rearward portion in communication with the central portion and open to the rear end portion of the accessory; a first plurality of openings in communication with and extending radially outward from the central opening, the first plurality of openings including a first radial arm slot extending from the central portion at 90 degrees to the U-shaped opening, a second radial arm slot extending from the central portion at 180 degrees to the U-shaped opening, and a third radial arm slot extending from the central portion at 270 degrees from the U-shaped opening; and a second plurality of openings not in communication with and positioned radially outward from the central opening; characterised in that the second plurality of openings are positioned between adjacent radial arm slots in the first plurality of openings; and that the rear end portion further includes a pair of chamfers (916a, 916b) tapering outward from the U-shaped opening to the rear end portion.