Set of four coasters. Real preserved flowers encased in resin. 
All resin will yellow over time. Keep away from direct sunlight. iCoat epoxy resin is made in the US. Is heat resistant but would not recommend using as a hot plate. Resin is food safe since cured.
Resin is non-toxic resin that is safe for food contact. The heat generated from a hot mug will not damage the resin surface. However, hotter temperatures such as that produced from a frying pan or casserole dish straight from the oven may well be too hot for the resin surface, so I do not recommend coasters be used for hot plates. Clean using a damp cloth.  Is recommended for use up to 120° F. Resins tend to yellow over time. Store in a dark place when not in use.  These pieces are offered at a discount since some yellowing has already occurred. It does not change the function of the coaster.