Glo T5 Linear Fluorescent Bulb Aquarium Light Fixtures, 24-Inch Built-in, high-efficiency parabolic reflector for maximum light reflection Easy to install, integrated extension brackets for a variety of aquarium lengths - Integrated suspension tabs to install above aquarium Aquarium mounting brackets, allow 4 secure vertical light levels , Two A3900s make up the A3899 Compact size allows the use of multiple units for highlight applications End caps for safe, reliable performance, Water resistant Compression-fit bulb