I got these coasters because I figured they would go great with the stainless steel appliances in the kitchen.  They look great however the edges are a bit sharp and as your drink sweats, the water runs down the glass and over the edge of the coaster so when you move the coaster, you still end up with a ring on the table.  There is some sort of foam under each coaster that keeps it from sliding or scratching the surface of your table but it doesn't absorb any liquid or prevent a ring.