Fit, but not exactly the same.
I bought an IM net top kit to make some tops for my 120. I was not going to be able to use it as designed,so I had to modify it some as the kits are intended for a rimless tank. I bought a pack of these to use as I'd need a few more than came in the kit. They do fit the metal rail of the IM kit just fine, but they are not exactly the same as the ones you get in the kit, nor on the top I got with my AOI 40 cube IM tank I have. Those have these little wings out each side. I assume again it's because they assume a rimless tank and those wings are what sit on top of the rim of glass or acrylic.
These sit down in the groove for a rimmed tank. This works for me as my tank is rimmed, but I now had 4 with wings and 4 without. As I was not able to make what I needed out of the kit I originally bought, I have to purchase another kit, so I'll have all the winged tabbed ones I need.
I guess the moral of the story here is these are not direct replacements for what you get in their kits or in their AOI tanks (at least the one I got), so don't expect them to be replacements for those. If you want a rimmed build buy enough of these to replace all the corner pieces that you will need from a kit. Or if like me and you have to purchase another kit you then have options. I like the look of the winged ones and it makes them a bit easier to get out.
It would also be nice if BRS could source some of the winged corners so we could have options when needing to replace those.