A portable system for imparting a reciprocating motion between a driving member and a driven member. The driving member has an upper and lower surfaces joined by one or more edges and includes a battery-powered drive mechanism. The driven member includes a treatment surface. First and second spaced apart studs extend from one of the members, and first and second spaced apart slots are formed in the other member. A locating recess is formed in each of the slots into which the studs are received. The drive mechanism is connected to one of the studs to impart a linear reciprocating motion thereto when the driven member is attached to the driving member. The connection between the driving member and the driven member is effected by each stud being entered into the respective slot and then moved into the respective locating recess by a twist-fit action.