Specifications: Top length: 13 inches, bottom length: 14.1 inches, height when in use: 6.1 inches Material: Iron. Hinges have two position functions: sofa and bed are suitable for sofa beds or you can make furniture yourself. New design: These hinges differ from standard hinges in that they operate from the front. When you lift the seat, the hinge will click and then release. When the frame is placed on the bed, when you lift the seat, it will lock with a click, and then you tilt the seat downwards, while the back of the seat rises to form a lounge position. Easy to use: If you lift the seat from the bed, you will lift it until it clicks twice. When you tilt forward, it is located in the sofa position, which is very suitable for carpenters to make their own furniture. With these adjustable hinges, you can convert the sofa into a bed. Packaging includes: 1 pair of adjustable spring mechanism futon hinges (left right) Features: This DIY adjustable spring mechanism with a futon hinge hardware is suitable for sofas or you "