If it fits, it works, right?

No, not necessarily. The connections are little pieces that fit over the drawer rails. I was wondering if those are a standard size, since I will also have the powder-coated steel drawers with a rail, but not IKEA brand.

Even though the Ikea drawers are made by Blum, the Rationell inserts will not fit Blum's own drawers. We have an ikea kitchen in one house and the Blum Tandembox in a second. Annoyingly, the accessories are not interchangeable between the two.

I have the same question. I have two places I would like to use rationell drawer systems with the cabinets and can't figure out if this is possible - or how to order dimensions to ensure it would work.