In view of problem of incorrect operation because that decelerate switch of electric control system of hoist and synchronous switch of backup protection device of hoist all used single tongue tube. a mine-used magnetic proximity switch based on double tongue tubes was designed. Working principle of tongue tube was analyzed. structure. https://www.animationbengal.com/?w=top-sale-napoleon-perdis-the-one-concealer-on-sale-great-pick