Custom, approx. 4"x4". Made of neoprene with a non-slip back. Neoprene is a synthetic rubber that is flexible and stands up to temperature fluctuations, so it is sure to withstand your hottest and coldest beverages and won't move around or be compromised by condensation. The printed top is a polyester fabric, so condensation absorbs into the fabric. Email picture(s) to DoMeAFavourSav@gmail.com and include order number. Due to difference in monitor calibrations, colors may vary slightly.