Looks like harden steel, I call Jim Arvis to ask what to cut it with, he said there all aluminum, this coupler came strait from Mercury.

I think all the long snouts are steel. Merc part # is 861523A7. They make the standard ones in both aluminum and steel.

I stand corrected, it is some kind of steel but soft

I have heard that the one with the long steel snout will handle more HP than the aluminum one. They are supposed to be interchangeable though.