Wudd you say?? It's our rubber!
Polymer47 is our proprietary rubber blend that creates our truly odor proof seal. No one will smell your cargo. Now, we do use Food Grade silicone in a few of our products but Polymer47 is what is used in all our caps and sleeves that are part of the odor protection of our products.
We have picked the proper blend of polymers (rubber) to best eliminate "gas permeability" which is how odor is transported through rubbers like silicone. Silicone rubber has 450 TIMES the gas permeability of our rubber blend. Man, it's just science. So if a competitor claims to be smell proof but is using Silicone in their designs we would find that claim very difficult to believe. These products were custom designed and tested exhaustively to make sure we deliver the experience you are looking for. They are very durable and the grip of the rubber ensures it will not "slip" out of your pocket at the wrong time. POLYMER47 also resists sticky things as well or better than silicone.
If you try us, we think you will like us. If you don't what you receive we have a 30 day money back guarantee*. Always free shipping. Always friendly service. Got a question? let us know.
*Subject to our return policy (unused product). Did you use it and not like it? Let us know and we will try to work something out.