Instead of use of the waterproof cover, {HEAD ~ the axial gap} may be controlled in {TAIL ~ size} thereof 
controlled in
Instead of use of the waterproof cover , { HEAD ~ the axial gap } may be controlled in { TAIL ~ size } thereof
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL OTH