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 Material - it is strong, solid and sturdy, exquisite workmanship, aluminum alloy frame and stainless steel screws that can be reused many times 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 Color: silver, yellow Material: Aluminum alloy Small size: 3*2.4*2.4cm Large size: 6 x 2.4 x 2.5 cm Package Contents: 6 x Sliding window locks with keys Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.