The device is designed so that {HEAD ~ the snapping sound} caused by {TAIL ~ the plunger} hitting a wall synchronizes with the impact on the muscles felt by the user during a hand motion 
caused by
The device is designed so that { HEAD ~ the snapping sound } caused by { TAIL ~ the plunger } hitting a wall synchronizes with the impact on the muscles felt by the user during a hand motion
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH