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