If You Could Only Use One Mechanical Pencil for Life, Which Would It Be?

I thought, "What of there was only one mechanical pencil you could buy for the life?What would it be?"

I decided on some criteria for my use as I do drawing: 1. Durable - Ideally complete metal 2. Functional 3. Design 4. How it feels in hand

After some googling, I thought it to be Rotring 800, as it fits the criteria. But what do you think?