The drive apparatus can be modified, with the addition of a gear and {HEAD ~ chain}, to reset or activate steel or {TAIL ~ other reactive targets} 
The drive apparatus can be modified , with the addition of a gear and { HEAD ~ chain } , to reset or activate steel or { TAIL ~ other reactive targets }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL