多重安全保护电路设计。
具有多重安全保障及自锁功能，无需别家任何栓门器材。
Three, with multiple security and self-locking function, do not need any other door equipment.
设有过载保护、断绳保护、工作高度保护等多重安全保护装置。
Safety device include: overload protection, wirerope break protection, height limit protection.
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