National Hardware N351-023 Spring Hinge, Steel, Satin Nickel, 37 lb

Hello Abel, Using the provided hex wrench key, insert short end of wrench into the hole at the top of the hinge barrel. To disengage the inside locking mechanism, apply a downward force. The wrench will sink about an eighth of an inch, holding that downward force turn the key counterclockwise to release the tension. To tighten spring follow same steps but now turn the hex key clockwise. If there's any additional assistance that we can provide, our Support Team is more than happy to help at 1-800-346-9445 option 3. Thank you, National Hardware