Klir Filter 4" Flow-Diverting Cap

Made sure you check your sump to see if the filter sock holes or oval or round. This is made for round 4' filter sock holes

Yes, it actually measures 4", so the hole size must be larger. The Klir Di-4 ships with 3 adapters to fit various sump filter hole sizes or shapes, this only fits one. Alternative sizes include the 4.25" adapter and 3.9" adapter, actual size. My Waterbox sump has the smaller size opening of 3.75", so I installed the 3.9" on the Di-4. While it is great the other adapters shipped with the Di-4, this flow-diverting cap will not fit my sump.

While this is the right size for the hole I was looking to plug the overall size is too large to fit into the portion of my sump I was looking to use it on. This is not the manufacturers error but mine. The piece appears to be quality and I'm sure it would do the correct job should I have done the work on my end.

The product needs a remake and softer edges i cut my fingers with it with just pressing it down and its plastic so how in the world did it cut me also there is a design flaw with just a small pressure in the sump the cover lifts up by its self with the water slamming it fixed the issue with wrapping a rubber band around it for a tight fit in the sock hole acts like a o ring preventing water to go inside of it and more of a tight fit

Doesn't fit Waterbox 90.3 sump

This item doesn't fit the Clearwater CWT 35-30" sump sock holder without modifying the size 1/8" Atleast the Klir fleece drop in unit came with 3 different sock holder size rings. The flow diverter should also come with other sizes for its cost.

This doesn't fit on any red sea aquarium...... its 4" and red sea socks holders are 3.5". Other than that its good.