This the listing is for hardware only,No Instruction is included, please check if it is exactly the one you need before your purchase.Lift Up Coffee Table Mechanism Hardware Fitting Furniture Hinge with Gas Hydraulic.
 
Turn a normal coffee table into a tricked-out coffee table. Made by heavy duty metal(won't bend).

Overall length and Width and height when in folded position: 27 3/8 inch ( L) x 13 1/2 inch (W） x 3 7/8 inch (H). The top raises up 9 inch and forward 8 1/4 inch.

Screws are not included (you may use bolts, machine screws, wood screws or whatever you feel necessary for your particular project).No instruction is included.

The specs say it will hold between 100 and 200 lbs when opening.
 
Note : Each Gas Hydraulic Lift has 66 lbs of force. In other words, you need the top to be 132 lbs to hold that sucker in closed position. Or you can find a suitable clasp at a local hardware store to hold it closed.
 
Package includes: 2 hinges and 2 buit-in Gas Hydraulic - enough to do one coffee table (or whatever you want to use it for).