I thought I'd clarify what this is, as it's not clear from the Omlet website and there's no picture (I have submitted one for you Omlet, hint, hint !)
It's the flat black metal piece which slides into the bottom of the Eglu Classic to secure the top on, with the lynch-pin at one end which you have to remove and slide this bar across to remove the lid to clean inside it.
This is just the bar, doesn't include the pin.
I needed a replacement as after several years ours had rusted through at the non-pin end and the tab there was about to break off.
It was a bit difficult to get out initially, as it has notches to prevent you pulling it out too far, but persevere and it will slide all the way out - either pull the non-pin end, or of the tab breaks off like mine then stick a screwdriver through the pin-hole and pull it out using that as I did.
Sliding the new one in was easy.