As is normal for the internet I'm going to give you an answer to a question you didn't ask
Well, sort of. If you are not fixed on the "valves" but are looking for in ear foam plugs then it is well worth getting one of the trial packs from these people. I've found that the critical thing with any ear plugs, or similar, is getting the right fit and so the trial pack allows you to try out a vast range of foam plugs to see which work best for you. Foam has the advantage of giving a higher attenuation than molded plugs as the foam expands after insertion to fill the voids, solid "plugs" can't do that and there needs to be some small gap around them to allow them to go in and out.
Ear Plug Assortment Packs - Ear Plugs
In some research it was found that contact between the rifle stock and over ear protectors could actually result in very high sound pressure levels as, of course, plastic and metal makes a much better conductor of sound than air. Given this, especially with a moderated rifle that may well be beyond the level at which damage would take place with a reasonable number of shots, it is possible for over ear protection to do more harm than good.
Alantoo who posts on this forum acquired some Peltor/3M LEP-100 in ear electronic plugs, these are not custom fitted but use plastic or foam tips in the ear, and his reviews encouraged me to do likewise and I'm very impressed with them. I was, basically, happy enough with solid foam plugs for rifle shooting as with a moderated rifle I only used plugs on the range but wanted to hear what was going on around me when shooting with the shotgun. Again, the key with the electronic plugs is getting the right fit with the ear tips but there are many very good solutions out there and I've even been able to get several that suit me, I'm fairly critical of fit or have a weird shaped ear canal. The down side of the electronic solutions like this is they are expensive and this may rule them out for you but it is worth giving it some consideration as protecting your hearing may be worth putting above buying some shooting gadget that you don't really need.