Totally Bamboo"s Non-Skid Coasters are a unique set of coasters that feature colorful silicone rings which prevent coasters and drinks from slipping. Set includes four coasters and holder. Colors include red, green, eggplant and orange. Set is made of beautiful, functional and ecologically sound bamboo. Unlike wood, bamboo is a fast-growing grass that grows to a harvestable height of 60-feet in about 3 to 5 years, growing as much as 2-feet per day. It has an extensive root system that continually sends up new shoots, naturally replenishing itself. It does not require replanting, making it one of the most renewable resources known. Totally Bamboo uses "Moso" timber bamboo which is neither a food source nor a habitat for the Giant Panda. Totally Bamboo"s cutting boards are assembled with approved food-grade glue - none of their products are made with formaldehyde-based glue. No dyes or stains are used in the manufacturing process. The pleasing designs are created by using the naturally occurring variations within the wood grain. Totally Bamboo prides itself on using only premium hand-selected bamboo, innovative design, exemplary craftsmanship, and fair labor policies. Overall set measures 4-3/4- by 4- by 1-3/4-Inch.