I had a 403 and it was a pain to work with, every time you had to open it it took about 4 hours to get to work again, had to leave it in a bucket because when you opened it it would leak everywhere. It is not like the more modern filters when the O-ring is built in, you had to manually put the O-ring on which proved to be very hard. The clips on the side would break off very easily. It was very hard to prime. Save up your money and buy a more modern filter, you will be much happier and it will save you a lot of headaches.