We use the Sun System 3 Commercial Grow Lights in our greenhouse and highly recommend them. These tough HID lights are designed to withstand high humidity levels found in greenhouses. 

Guaranteed not to rust, Sunlight Supply uses powder-coated extruded aluminum ballasts with 95% reflective German aluminum Sunstar reflectors. The reflector features 6 adjustment points to customize the light pattern. They're made for high output and diffusion with the durability to last years.

The Sun System 3 Greenhouse Lighting Fixture comes with:

Ballast
Sunstar reflector
Mounting hardware
Built-in hanging brackets
Instructions
Optional HID Bulb available (choose below)

New Features: Quad tap ballast leads (120, 208, 240, 277) are all accessible in the junction box. This allows for easy installation without opening the fixture housing. Also, the EZ Cap door (patent pending) allows easy access to the capacitor without having to de-install the entire fixture.

UL and CUL listed for damp locations. For the ETL listing to apply metal halide lamps need to be "MP" protected MH lamps. The Sun System 3 Commercial Grow Light is a built-to-order item and takes 1 to 3 weeks to ship. Entire system weighs 28 to 35 pounds, depending on wattage. 2 year replace or rebuild warranty.