biohacker
H.R.E.A.M
Your best best is directly from S&B...it's only a few dollars for the entire kit. I was fortunate enough to have a kind member donate an extra so maybe you might get lucky, but they seem to be the most elusive and easiest to ruin/lose. I wish there were bigger disclaimers on how to properly install that small o-ring, because every time I wrecked or lost one - it was obviously my own fault! I have moved on from the Mighty since, but unless there is something that crushes it i'm pretty sure i'll outfit my kit with another next summer, which is the only real time I need a portable.