First impressions can be deceiving. At first I thought this shelf unit was a clever re-use of a standard slat wall backplate (B/P) in a slotted vertical surface. Upon closer inspection, the offset is far greater than slatwall offsets, so the backplate is not stock. Check the back and you find the already oversize offset is not even the full depth of the substrate, so the material had to be be countersunk to accept the backplate. Possibly the backplate is made to extend through one layer of forward facing material, while this use is double faced, and double thicknessed … hence the countersink to allow use of a single thickness backplate offset. In any event, interesting routing work creating the slot and countersink in particleboard. CLICK the thumbnail for what you first impression view would be.
For an amalgamation of unusual attachment methods SEE…
“Hinge-Mount Mop Rack”
“Savvy Straight-Entry Wire Basket”
“Squared Wire Basket for Endcap Mount”
“Bath and Body Slatwall Trays as Shelves”
“Backplate Kaizen at Work”
“Slot Bar Mounts Over Slotwall”
“Straight-Entry Pegboard Bin”
“Inverted Endless Basket”