Eshopps' Float Valve offers a simple solution to maintain proper water level. Use the Eshopps' Float Valve as part of an automatic top-off system you create to replenish aquarium water lost through evaporation. Adjustable acrylic mounting frame allows a full 6 inch range of water level adjustment for versatile installation options. Features nylon screws (no metal parts) for corrosion and rust-free use. Includes 3-1/2x 2in diameter Float, Valve Assembly, 1-5/8x 1-5/8x 7in high acrylic mounting frame, and a 7 foot length of 1/4in tubing that attaches to your water source.