spot on.Hithere said:Is it a purge valve or something?
PsiFox said:umm a snorkel?
cleanbluesky said:It lets the water out of the bottom which saves you puffing it all the way out of the end of the tube... snorkels are pretty boring but it beats nitrogen narcosis
Helps if you stop being under water first .The_blue said:after going under water, breath in very slowly to get the 1st breath then blow fast to clear the water and then breath like normal