The box end 10 of the wrench 1 has a smoothly arched notch 101 smoothly curved inwardly at the smooth inside wall thereof and is axially extended to {HEAD ~ the topmost edge} of {TAIL ~ the smooth inside wall} 
of
The box end 10 of the wrench 1 has a smoothly arched notch 101 smoothly curved inwardly at the smooth inside wall thereof and is axially extended to { HEAD ~ the topmost edge } of { TAIL ~ the smooth inside wall }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL