Neoprene, nitrile, and pads have been on the market for some years. They are made of closed synthetic foam allowing them to create a tight seal, are incredibly quiet, and are fairly easy to install. They are also sound absorbing. Another problem we noticed is that neoprene can shrink over time if it is not treated properly. This can cause leaks.
(C) 2016 - by Lohff & Pfeiffer - 7304 Carroll Avenue Suite 194 - Takoma Park MD 20912 - USA - Phone: 812 929 5556 - email@example.com