Plastic barrel pressure valves

[brouwpa]

First of all, I would like to thank Martin Campling who very kindly  offered some barrel taps that I couldn't source online.  This offer was extended to other stuff that Martin no longer had a use for!!

Anyway, I have some older plastic barrels that have no pressure release valves and having googled it the following turned up on Ali Express:

Pressure Relief Valve(PRV) with 1/4" Male NPT Stainless Steel 304 Homebrew Kegging Parts DIY Keg Component

Now I have no idea what I am looking for, but would these do the job?

Thank you for any advice

Cheers

Paul