Scottri:"I would not be looking for a T1 however since the current model is the T2. T1's have been sitting on the shelf for a while if they are available"
The above statement is incorrect. The T1 is the Titanium 1st stage. The T2 is a chrome plated brass first stage. Both are current, the T1 is not older than the T2.
Wrong!,
T2 = Titanium 1st stage / 2nd stage, good to 40% nitrox
M1 = Monel 1st stage / mix of titanium & zirconium, good to 80% nitrox
B2 = Brass 1st stage / Titanium 2nd stage, good to 40% nitrox
Z2 = Brass 1st stage / mix of titanium & zirconium, good to 40% nitrox