Wide Usage:: can be easily applied to most environments; By keeping the windows partially open and closed, the burglar-proof and thieves can prevent children from falling and protect the safety of their families while improving air circulation Quantity:10 pieces upgrated double sliding window locks with 10 keys; Double Window Locks:: Double window locks can be apply to the heavy doors or windows to increase safety. And it will be more strong, solid and sturdy, exquisite workmanship, aluminum alloy frame and stainless steel screws that can be reused many times. Easy to Install:: there is no need to install extra tools, it equips a hex key in each window locks, holding on the track by key control. Designed for horizontal/vertical windows and sliding glass doors; Not for plastic window frames. Size:6*2.5*2.4cm Package include: 5*Locks