The knob 80 has an annular portion 82 arranged for frictional engagement with the exterior surfaces of the rear wall 66 on {HEAD ~ each side} of {TAIL ~ the slot} 76 
of
The knob 80 has an annular portion 82 arranged for frictional engagement with the exterior surfaces of the rear wall 66 on { HEAD ~ each side } of { TAIL ~ the slot } 76
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH