How it's made. Every upright in a pallet rack is punched with teardrop holes every 2 inches, and the panel's hooks go in the same way a beam connector does: the head is smaller than the round part, so it goes through; the panel drops into the narrow slot and the head, wider than the slot, holds it. No tools, no fasteners, lift to remove. Slot sizes vary by maker, so pick A, B or C, or type your own from a caliper - the fit strip has all three and costs a few dollars. Made face down with the hooks standing up, in PETG. Made for signs, labels and tools, not for load.