The best is Surefire.
The 2nd best is Streamlight.
Either one of those is a good option.
I agree with this 100%, however, I purchased 2x tlr1s', and one of them loses its constant-on while firing (switch loses its hold). Get the surefire.
Does the Gen 2 have a rail??
I have Streamlight's LTR 1s on all my guns, long and short