Uni Filter?

[RedRaider]

I know the uni filters are the same for the 400ex and the 450. My question is how big is the hole at the back end of the uni filter where the inner brace comes out of the filter? I tried a white bros filter for a 400ex and the hole is twice as big as the 450 stock filter. Are the uni's the same way, with the big hole?

[BSTURDIVANT]

UNI's don't use the rear brace! attach in front only! with it's on cage.

[RedRaider]

Thanks man thats what i needed to know. I've never used a uni before only white bros and k&n.