LOVE THIS BOTTLE. Have had this bottle now for a few weeks and the ability to keep drinks cold is phenomenal!! I purchased one of these for myself and a Sports Tanka and cover for the wife. On adding a dozen ice cubes at the beginning of the day I still had small cubes 4 hours later after refilling with cool water from my Mega Tanka! The drink was still cold after again refilling the Thermo Tanka some 6 hours later. Best Bottle. Just bought 4 more for the Mrs and Kids. Thank you HealthPost and EcoTanka. It is prone to dents if dropped. But hasn't affected the performance of the bottle one bit. Still LOVE IT!!