These are great!  They absorb all the sweat off your glass or can. I live where its hot year round, and have tried many varieties of coaster, many of which either did absorb at all, or just transferred the wet to the table underneath.  Because they absorb, when you pick up your glass, the coaster stays behind.  I have broken many coasters when the adhered to the glass, and then fell to the floor. Buy lots of them.