Difference b/t Rayfoss RF532-50mW: QBT, QMT, QST, QGT?

Could someone please explain the difference b/t the following Rayfoss models: RF532-50mW QBT, QMT, QST, QGT? I looked at the specs and they seem the same. I emailed customer service but have not heard back.

Also, I am looking for a green laser that can be seen in the daytime and that is durable enough to withstand some humidity, possible rain, and staying in my pocket for long hiking excursions. Are these waterproof Rayfoss a good choice for the money? Thank you!

Rayfoss emailed me back, they are the same except the difference in colors.