It is a first-class T-Handle Hex Key with 3 heads (!!!). The handle can be moved. No cheap loosy China scrap!!
This one is one of my best tools I ever had. Don’t waste your time and money to buy this everywhere-available-cheap-chromed Hex Key (Inbus) sets, you will always loose! This tool has 3 (in words: THREE) bits!
You need a 5 mm T-Handle Hex Key for the 2 screws to fix the stanchion tubes into the fork crown (all the older Marzocchi forks form the 90’s) and for the 4 screws (2 each side) to fix the stanchion tubes into to crown (DH3).
Available on back-order