Apexstone 2pcs 250N/56LB 15inch Gas Spring/Prop/Strut/Shock/Lift Support with L-type Mounts Force:56 Lbs/250 N(Per Strut),Length (Center-to-Center):14.96 inch(380 mm),Compressed Length (Center-to-Center):9.06 inch(230 mm).Bracket Holes' Size: 8 mm(diameter),8 mm(diameter),10 mm X 8 mm(Length X Width) Ideal for supporting the door/lid to keep it open,Support opens lids to a maximum angle of 150 degrees,it fit for the door/lid which the SIDE LENGTH is MORE THAN 35 inch , the WEIGHT is MORE THAN 50 LBS for EACH GAS STRUT If you want to open the lid at 90-120 degrees, the mounting point on the lid is at the 120-130 mm(4.72-5.12 inch) to the hinge's direction.If you want to open the lid at more than 120 degrees, the mounting point on the door is at the 75 mm(2.95 inch) to the hinges direction.If you feel the it's too powerful, you can move the mounting point 20 mm(0.79 inch) towards the hinges's direction ,while if you feel it's too weak,you can move it 20 mm(0.79 inch) towards the opposite direction Instructions and Screws NOT included,HIGH PRESSURE inside,DO NOT open it,DO NOT compress it by hand,DO NOT approach the high temperature CAUTIONS: PLEASE DO READ the IMAGES and DESCRIPTION CAREFULLY before placing order.If you are not sure if it's okay for your project,you can contact us before ordering this