Rainbow D4 / D4SE Clamp Ring Segment

The clamp ring that holds a Rainbow's upper housing down onto the water basin is built from segments rather than one continuous hoop. R2585 is a single one of those segments, for the Rainbow D4 and D4SE.

Segments crack. They carry the load every time the unit is opened for a water change, and the plastic grows brittle with age and heat, so one lets go while the rest still look sound. With a segment split or missing, the ring cannot pull even pressure the whole way around, and the seal opens on that side — you get spitting or leaking at the seam during use, and suction softens because the machine is drawing air where it should be drawing through water.

Order by how many you need. While it is apart, check the remaining segments for hairline cracks: one failure usually means the others are the same age and heading the same way.