Kev1-1:
I have one. It is a Nylon pouch which has a elastic strap sewn inside the pouch to retain the M3 in the bezel down position.
There is no flap or any other means to retain the flashlight.
I have not used mine because it would be too easy to loose the flashlight.
SOE makes a nice pouch with a retention strap and buckle for the M3 in the bezel up position. I have two of the SOE pouches and use them regularly.
www.soegear.com