Hydraulic mechanism for under-mattress storage. Includes heavy-duty steel brackets, powder-coated black, along with screws for bed deck mounting, and gas pistons to hold the bed in a raised position.How to choose the correct piston weight rating (XKANG..):
1) Add the weight of your mattress + weight of the selected bed frame (XULT...) = Total weight
2) Choose the piston with the next highest weight capacity