A medical device comprises a catheter, a retractable sheath, and a rolling membrane. The ball may be held in location by contact with the receptacle at at least two positions. In a preferred embodiment of the invention, the applicator wand is hand held, the applicator head having an inlet, an outlet and a body therebetween, the water and fuel being supplied to a steam generator and burner within the body of the applicator head which generates steam and hot air adjacent to the target area for application through the outlet to the target area. A portion of the data andor metadata associated with the represented objects may be prefetched to a memory. The instant-draw model and the differed-draw model are supported. The second side wall portion is connected to the second surface and includes a non-scalloped surface.