YASHANG Specification: Top Length: 13", bottom length: 14.1", the height when use: 6.1" Great Material: Made by high quality heavy duty steel These hinges have 2 positions functions: Couch and Bed Suitable for Sofa bed or you can DIY for your own furniture New Design: The difference between these hinges and the Standard Hinges is that they operate from the front When you lift the seat the hinges click and then release. When the frame is in a bed, you lift the seat and it clicks once and locks, and then you tip the seat down, and the back comes up at the same time and makes a lounge position Easy To Use: If from the bed, you lift the seat until it clicks twice, when you tip it forward, it is in the sofa position Perfect for woodworker to make their own furniture With these adjustable hinges you can converse your sofa to bed Package Included: 1 pair of Adjustable Spring Mechanism Futon Hinge ( L R) Features: This DIY adjustable spring mechanism futon hinge hardware is suitable for Sofa bed or you can DIY for your own funiture. Also is erfect for woodworker to make their own furniture. If from the bed, you lift the seat until it clicks twice, when you tip it forward, it is in the sofa position Perfect for woodworker to make their own furniture With these adjustable hinges you can converse your sofa to bed. Specification: Color : Black Top Length: 13" Bottom length: 14.1" The height when use: 6.1" Thickness: 3mm Package Included: 1 Pair of Adjustable Sofa Bed Hinges (LR)