The oscillating arm 24 may be rotated so that {HEAD ~ the push rod} 21 is aligned or not aligned with {TAIL ~ the massaging pin} 3 
is not aligned with
The oscillating arm 24 may be rotated so that { HEAD ~ the push rod } 21 is aligned or not aligned with { TAIL ~ the massaging pin } 3
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH