Abstract: A laundry treating appliance includes a rotatable drum for receiving a laundry load. The rotatable drum includes a cylindrical body with an cylindrical wall, and a cover at one or both ends. The cover has an annular groove formed by a first, second, and third walls. A fourth wall extends from the second wall. A first land is secured to the third wall and a second land is secured to the fourth wall. An adjoining piece has an adjoining wall that is attached to and extends between the first and second lands. A hollow space is bounded by the adjoining wall and the second and third walls. A movable mass is disposed in the space.