I need to have a bit of a clear out and one of the items that has to go is (was!) my old crack bottle DSMB. I bought this sometime ago and it has sat in a drawer being annoying for a few years now. Way back when, I used to operate it following the standard protocol of my old PADI club - crack it right open and let it fly.... I’ve known the drawback of this method for a while now so I thought that, prior to selling it, it would be prudent to carry out a few ‘tests’ to ensure the fucker was not rotting from the inside. The bottle was attached to a full fifteen litre of mine, which was then opened up. I gently opened the crack bottle a smidgen.....and it held. Fucking brill thought I, as I very gradually increased the pressure.....suddenly BANG, not so fucking brill now. Oh well. At least I’m not stuck having to refund some poor sod that I might have sold it to, or having to explain to a coroner how it was just a simple accident that the buyer ended up with a crack bottle embedded in their bonce.