Attwood Marine Aerator Spray Head Use on livewells that have built-in overflows or recirculating systems. Mounts on side of tank. 90 fitting for installation in tight spaces. Rotating head with O-ring adjusts and maintains flow setting. Removable head has an interference-fit thread design that will not allow it to vibrate or blow out. Polypropylene construction. Can be installed on tanks with up to 58 wall thickness. California Residents WARNING Cancer and Reproductive Harm - P65Warnings.ca.gov