You wont need to tell your guests to use a coaster with these laying around. Use a coaster or I'll punch you in the throat. Definitely my most popular item! Set of 4, each coaster has a full 3.5" x 3.5" cork backing. Each coaster is 4" x 4". The image is transferred to travertine tile for slight absorbency. The more porous the tile is, the more absorbent it will be. Each one is handmade and unique. Tiles range in color from light to medium dark. Give your coasters a nice stand by pairing them with either a clear stained, black stained, vintage blue stain, weathered gray stain, or brown stained beetle kill pine handmade, hand cut coaster holder. By purchasing, you are acknowledging that these coasters are individually made by hand and in no way will be perfect due to the nature of the natural stone, each coaster will be different. They are intended to have that rustic look/feel. These tiles are not always smooth and may be rough on the top, and part of the image missing where there may be holes in the stone. I do my best to position the image where it will show best. These are not dishwasher safe and should be wiped clean with a damp cloth. Since each tile is made of natural travertine stone, no 2 will be alike. There may be slight abnormalities that make each coaster unique in their own way. Some will have more divots/holes than others. Some may not be perfectly square, nor exactly 4 inches.