The BROR shelves fit together flush when you combine two units, but if your units include the lower cabinet there will be a gap between them, and things you put on top are bound to fall into that hole.

This model allows you to fill that gap in a simple way. The hole is 31.4cm x 9.2cm, but in order to make it easier to print on a smaller printer, the piece is half-length (15.7cm) and you need to print it twice.

Use one of the short ends as the base for printing to keep things smoother. if you use the top as the base it should still work but the rounded edges will be a bit messy.