These extension bars are made for the Seed Starting Universal T5 Light Stand, allowing you to extend your growing height to 30 inches. We love this universal light stand, and so will you. It's simple, lightweight, very durable, and completely adjustable. It puts light just where you need it, so your seedlings and plants grow their best. It's easy to use and endlessly versatile. We think you'll get a lifetime of hard wear out of it, and we highly recommend it for starting seeds indoors, growing on seedlings before the season, and overwintering tropicals, tenders, and houseplants!