The TE Connectivity 5-100525-4 is a green coding key for the Z-PACK series of backplane connectors. The green color identifies the specific keying position — different colors correspond to different keying codes, so the green key only mates with a receptacle or header keyed for that same color.
Why the Green Color Matters for Your Build
In a dense backplane with multiple connector modules, the coding key prevents a power module from being plugged into a signal slot. The green key physically blocks insertion unless the mating half carries the matching green keyway. If you are populating a Z-PACK backplane, confirm that the header and receptacle share the same key color — mixing colors means the connectors will not mate, which is the intended behavior.