Safety First U-Pressure Fit Extension can be used to extend your Safety 1st safety gates. Keep your kids away from the stairs, kitchen or out-of-bound areas in your home. This extension can be used alone or in combination with other extensions ( 7cm , 14cm or 28cm ). The configuration for each safety gate is shown on the packaging or in the instruction manual. ONLY compatible with the following Safety 1st gates (click the following links): Easy Close Metal Simply Close Metal Quick Close+ / Quick Close ST Autoclose Flat Step Gate Recommended for babies 6-24 months.