Form Mixxit White 3 Cube shelving unit (H)1080mm (W)390mm. The MIXXIT storage range is the simplest concept that allows you to create something that is completely versatile and unique to the room and space you need it in. Leave the shelves empty to display your favourite items or add the ranges storage boxes to neatly tidy away other things. Create stylish and functional storage in any room – use the shelving cubes to openly display your favourite items or pair with the matching storage boxes to neatly tuck away everything else. 3 Cube shelving unit by Form.