The coasters are made from beautifully smooth tumbled marble tiles using a vintage Baltimore map. Each coaster measures approximately four inches square and has been backed with cork for a steady and secure footing on your furniture.The images are hand applied in a transparent medium to allow the color and texture of the natural stone to show it's character. The coasters have been well sealed to ensure durability for lots of use with both hot and cold beverages.The coasters offer a unique and eye catching way to display some small works of art in your home. Each set is lovingly created and attention to detail is of the utmost concern. I wanted to make a collection of rich, warm and personalized home decor... useful items featuring inspiring, beautiful and personalized pieces that you'll be proud to own and display for years to come.Please leave 1-2 weeks for production of this set. If you need your order by a certain date, drop us a line and we can most likely make it happen!Coasters can be wiped clean with a damp cloth... they are not dishwasher safe.