The nylon insert that goes in the the transom assembly to protect the shift cable sheath. Part # 14705 for my Alpha One. Not sure about the long one in the pic.
The nylon insert goes in the hole where the shift cable enters the outer transom assembly and passes through into the inside of the boat. The transom assemblies are the 2 halves that bolt together with the transom in between them, there's the inner and outer assembly.