Heavy Duty Galvanised Additional Shelf 1800x600mm Orange/Zinc 378890. Create the shelving unit of your own designs by adding in extra shelves to your existing heavy duty galvanised shelving. This extra shelf is simple and easy to insert as the shelves tap together simply. Shelves can be easily adjusted every 40mm at any time and require no nuts and bolts, making the whole process quick and easy. With a capacity of 600kg, this heavy duty shelving unit will hold everything you could need it to.