Lamp length – 15″ / 375mm to 18″ / 450mm T8 The Arcadia ULTRA SEAL controllers are the latest generation of their popular fluorescent lighting controllers, incorporating a number of improvements and designed to comply with the latest European aquarium lighting standards. •Easily adds additional T8 lighting to an aquarium. •Patented ULTRA SEAL waterproof (IP67) Lamp-holders. •Supplied with universal mounting brackets for installation on aquarium hood or walls. •Single Controllers from 6W-58W. •5 Year Guarantee.