Reinforced telescopic chain: Reinforce the chain, increase the pulling force, and thicken it and it is not easy to break Thickening materials: The materials is thick and full, the inner cores have a builted-in spring designs, which cushions the stress and is Enduring Zincs Alloys materials: It is cast with thick Zincs Alloys materials, which is not easy to rusts and age Spikes designs: Spikes designs is used, which is not easy to bounce and not easy to damage Single switches: Single to, redness mean to, black mean to open, and practical, Manufacturer: Kaeltsyn