LuxStar T5 4' x 4 Bulb Fixture w/ Grow BulbsThe LuxStar T5 4X4 bulb fixture is an economical solution that delivers perfect spectrum light to create healthy growth. As the fixture emits very little heat, so placing the lamp closer to the plant canopy wont be an issue. You can place the light on the top of the plants. The fixture uses ballasts that control the light output of the fixture. With the combination of high output bulbs and digital ballasts, you can create an immensely efficient light