a) A inverted cylinder, this kind cylinder is much lighter but the property is much steadier, the lifting speed can be 20% quicker
b) With limit switch
c) with optoelectric switch, it can test if there are cars or people under the platform. If there are, the platform can not lift down. Much safer
d) Electric release
e) in the electric box, except up, down, urgent stop button, there is installed with warning device