I have to agree with Blade. The black-out mask is the best I have used in over twenty years as a team leader, and instructor. We tried foil, tape, and plastic inside the mask. If someone panic's they have to remove the mask, take out whatever was used and then replace and clear the mask. Not too easy when the diver is having a problem. I have used the unit from DRI, and have had several teams make their own once they use the ones I supplied during class. Mine is getting a little thin and will need to be replaced soon, and the $10 is not too bad for a safe training device, where the student or team member need only remove the device, and see without removal and replacement and clearing their mask. Remember use the least risk to develop the best training scenario.
