Metal Shelving Hook (single)

I needed hooks for my metal shelves that i have, basically everywhere, like i assume most of us do (i have sets from storables and costco). This hook will work on either side or end of the shelves, which was tricky because the bars are actually a few mm different. The design is to attached to the top bar like a fork around it, that's the secret sauce. This is the single hook version, see my things for the double hook version.