I guess you mean the security bolt adapter/tool? Is it the original one supplied with the car or an after-market system? If the former, what you need depends on the type of security bolts fitted. MGR issued two types, the simple splined socket type (of which there are two versions, No11 & No12) and the McGard coded key and collar system. The most common ones are the first type No12. I have some photos somewhere which I'll post if you needthem.
EDIT: Managed to locate copies via another thread.
This is the first type
and the McGard type
TC