Nalgene's 24oz On-The-Fly bottle has a leakproof loop-top that swings open wide to reveal a contoured, high-flow drinking spout that's easy to fill at the fountain or sink. One-handed push button for easy open/close; locking bail for ultimate insurance against leaks. Sustain bottles are made with material derived from 50% plastic waste. Each bottle is created from resin powered by next generation recycling technology that transforms plastic destined for landfills into high-performance bottles.