Wilson,
This question leads me to the answer that has gotten me into a lot of ridicule on this forum. The question of quality of products that is geared for Lowe's and Home Depot. The products that I buy from a Rainbird and Hunter supplier is different from that of these ticket store's. I don't care what anyone has to say otherwise, because I use the 5000 and the 5500 series quite often. The quality is different and the overall durability of these heads is different. Do not under any circumstance use the Orbit brand as they are of poor seal, rotor and inner part quality. I have replaced heads on accounts after just one season of use. Low budget customers use the orbit brand and I will end up replacing them with quality heads after a season anyway. If you are in a pinch for head replacement...then it is your call but I don't want a useless repeat call next season on heads that have warranties.