A hollow compensating spool is slidably arranged within {TAIL ~ the hollow cage} between {HEAD ~ the cross sectional holes} 
A hollow compensating spool is slidably arranged within { TAIL ~ the hollow cage } between { HEAD ~ the cross sectional holes }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD