It's hard to review a piece of foam, but I love my ancient Sennheiser MD 431 microphone, a real studio workhorse, that'snot only great on vocals, but also on guitar cabs; much like the trusty Shure SM57, but actually with a more refined sound. I was amazed somebody actually carried spares for this old model, and after 20 years in use its foam has practically disintegrated.
Kudos to Thomann for carrying such items - perhaps rarely needed, but if they are needed, one is willing to hunt high and low to get one.