Common in the brand of strong light flashlight in the middle head and head flashlight,
Advantages: Simple and reliable structure, wrong operation may be small, the file position clear
Disadvantages: Some friends think this way can not be one-handed operation, is "brain residue" design, and some people think that when the head is loosened when the impact on the overall strength and contact. But there are actually a lot of packages that need to be tightened again after the head is loosened to adjust the light, such as my hand Olight M3x lumintop Td12 and so on, are so, I feel that this does not affect the overall strength AH. Even if it is my TK12, need to loosen the head into the next brightness, but also just need to loosen a little bit better, the head of the rectangular thread is very close, plus the role of O-ring, in the state of loosening in the water for half an hour, the barrel body without water.