The Gatorade Gx Insulated Bottle is sturdily built. The smaller drinking cap is secured to the larger filling cap with a plastic "strap." The joint between the "strap" and the cap is a metal axle, allowing the unit to rotate once the small cap is unscrewed. This is a unique feature, however my only remarks agains the bottle are the position of the drinking spout. Previous bottles have had the spout closer to the edge of the main cap, which might be more ergonomic than having the spout in the center of the lid.