A Rocker Spring Plate is made of fiberglass and designed to bend without breaking. These plates support the seat portion of an outdoor chair and have just enough give to allow the chair to rock back and forth. These plates wear out over time, start to splinter and need to be replaced. Failure to do so can result in the failure of the old rocker spring plates and possible injury to the occupant. Choose the plate that matches your original OEM installed spring plate. Use your old plate to drill the appropriate sized holes for your application. Please follow your manufacturers guidelines for this repair. PartsPuppy.com is not responsible for improper or faulty installation. All installations should be performed by a trained professional.