Available from cutter - Q5 WD. I have one but have not tried it with an optic/reflector yet - I have decided to cut back my photon habits as the wife rolls her eyes everytime I get my electronics bits and bobs box out.
Curiously, the WD tint was the highest VF I have - 3.8v at the PSU rather than 3,7 for most others (including an R2) - I know that measuring at the PSU is not correct but the conditions were the same for all devices