Preferably, {HEAD ~ the invention} relates to a device, wherein {TAIL ~ the device} is smooth and without sharp edges 
Preferably , { HEAD ~ the invention } relates to a device , wherein { TAIL ~ the device } is smooth and without sharp edges
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH