This is an AA display or storage system square bar bracket. This one is a center bar bracket. These are used on slotted rails that are attached vertically to a wall or a framework display. Yours is chrome plated and has in insulator so the chrome on the bar that goes in the slot doesn't get marred. The thumb wheel tightens the bracket to the slotted rail so it does not dislodge accidentally when installed. I have supplied a couple URL's that show different styled of brackets. These are made by many different manufacturers. The maker of yours is unknown.

This is an AA display or storage system square bar bracket. This one is a center bar bracket. These are used on slotted rails that are attached vertically to a wall or a framework display. Yours is chrome plated and has in insulator so the chrome on the bar that goes in the slot doesn't get marred. The thumb wheel tightens the bracket to the slotted rail so it does not dislodge accidentally when installed. I have supplied a couple URL's that show different styled of brackets. These are made by many different manufacturers. The maker of yours is unknown.

References:

https://www.jmeequipment.com.my/aa-upright-bracket/aa-upright-bar-bracket

http://www.nikorex.com.sg/index.php?ws=ourproducts&cid=92981&cat=AA-System&su...