What is the shipping dimensions for this item?

The shipping dimensions are approximately 18.5" x 7.5" x 25.5".

Hope that helps.

P.S. This item is currently out of stock with an expected arrival date in our warehouse of end of May.

Is this available in black or can it be back ordered?

We do not have the 5-tier available but we do have the 4-tier with the 250-lb shelf capacity.

https://honeycando.com/products/4-tier-black-14x36x54-250lb

What are the dimensions of this shelving unit?

If you scroll through the product page images you can see one with the dimensions:

This unit is 24"W x 72"H x 18"D

I'd like an additional shelf for the SHF-01054. Can I buy 1 separately? Thanks

Here is a link to a page on our site where you can purchase an additional shelf.

https://honeycando.com/collections/shelving-components/products/18x24-chrome-shelf

Hope that helps.

Is the spacing of the shelves flexible or must they be placed in a specific place?

Shelves height can be adjusted at 1-inch intervals.