Neoprene™ and Scuba Foam™ are polyester fabric over open celled thick rubber commonly used for wet suits. The polyester fabric makes it an ideal substance for printing applications. Relatively new on the market is the rubber coaster -- a natural extension from the now ubiquitous rubber mouse pad. Flexible slip-resistant and durable rubber coasters also are washable. As for your promotional mailers you will find the thinner coasters fit perfectly in envelopes and add a nominal postal up-charge due to their light weight.