The metallic parts 11 and 21 thus brought close to each other will attract each other owing to {HEAD ~ the magnetic attraction} of {TAIL ~ the magnets} 14 and 24, with the result that the projection 26 on the metallic part 21 automatically engages the groove 16 in the metallic part 11, so that the coupling operation can be completed instantaneously 
The metallic parts 11 and 21 thus brought close to each other will attract each other owing to { HEAD ~ the magnetic attraction } of { TAIL ~ the magnets } 14 and 24 , with the result that the projection 26 on the metallic part 21 automatically engages the groove 16 in the metallic part 11 , so that the coupling operation can be completed instantaneously
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