The P-valve has a short but steep learning curve. Here’s what I learned in short order:
For the condom catheters you can size yourself up for the correct size unit by using the measuring guides on the manufacturers’ web sites. Hint, make sure you print at 100% and turn off scaling. Also, if you remember Castaza’s law and go down one size and you shouldn’t have any problems. For the Light Monkey barbed fitting I’ll cut about half of the tube off the catheter to avoid kinks from folding over. Kinks are bad and will cause urine to very quickly work its way outside the catheter.
You can usually get free samples from the manufacturers to try a couple sizes. Try them out wearing them during the course of a day before you try them diving.
For undergarments I have a couple sets of base layers, particularly fond of my Coldproof ones. Those are easy enough to change out to keep from getting your actual undergarments funky over multiple days. While I dropped the coon on the DUI Duotherm 300 onesie, I have a fleece sweatsuit for the warmer temps. But always wearing my base layer.
Probably the most troublesome thing I had was the p-valve routing. The DUI onesie has double zipper so I can run the hose in the bottom, put a loop in it and have it lay against my my thigh and connect it up. For sweatpants and other non-purpose designed garments, a button hole sewn on the inside of the thigh can facilitate routing. For the base layer I keep myself outside the fly. Make sure there’s no twisting on the plumbing. Remember what I said about kinks. And you don’t want to trim it so short that the the plastic bit from the plumbing is making contact with your skin. That will become uncomfortable quick.
The catheter you can put on in the morning before leaving the house. They are designed to be worn for up to 24 hours. I’ll use an alcohol prep pad to ensure good adhesion. For removal, a warm shower after I get home or that evening is easiest. A warm washcloth will also suffice to soften the adhesive.
The P valve is an amazing convenience. I find that I drink a lot more water during the day. No running to the toilet after a dive or sitting there in your own urine. No relief zipper that you might forget to rezip or damage. Just make sure if you aren’t hooked up you close the valve.
