Use these 54 Watt T5 high output fluorescent bulbs for your Tek-Light grow light fixture from Sunlight Supply. These 3000K (warm) high output lamps have an extremely high lumen per watt rating. 5000 lumens per lamp/54 watts = 92.59 lumens per watt. These fluorescent bulbs have a very low heat factor which allows the fixture to be hung very close the the plant canopy, raising light levels. This lamp is compatible with T5 electronic ballasts. Mix with 6500K bulbs for full spectrum effect.Note: T5 bulbs are included with all Grow Light Tek Lights. Purchase T5 bulbs separately for Aquarium Tek Lights.