My wife is a crafter and recently bought the IKEA Skadis system for her craft room. She really liked some of the Skadis accessories but complained that the container unit (203.207.98) was not deep enough for some of her items that she wanted to store in them. I modeled the extension with a 10mm slot in the center of the extension that slips around the top of the container. The whole extension is 40mm tall but with the slot, it gives a total of 30mm total extension to the container unit.