The grooves on {HEAD ~ the front end} of device face proximally and are disposed on opposite sides of the device in {TAIL ~ alternating fashion} 
The grooves on { HEAD ~ the front end } of device face proximally and are disposed on opposite sides of the device in { TAIL ~ alternating fashion }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL