Abstract: A wrench-adapter for rotating a plug of a casing for an in-the-pan type of oil filter. The wrench-adapter adapter has a tubular main housing that is telescopingly received in the plug with a portion of the main housing projecting outwardly of the plug. A plurality of pivotally mounted jaw-members are mounted in the outer circumferential surface of the main housing with each having a portion projecting into the hollow interior of the main housing, and a portion projecting away. An actuator-member causes partial rotation of the jaw-members relative to the main housing in both the clockwise and counterclockwise directions, in order to bring one of the sharpened corners of each the jaw-member into contact with the annular interior surface of the main housing of the plug. The actuator-member has a central hollow interior for receiving therein the head projecting from the recessed front surface of the plug.