The On the fly OTF Sustain bottle has a hinged cap with a lock against opening and spilling the drink. It is easy to open with one hand and thanks to the wide screw cap, you can easily refill it. Of course, there is a silicone seal, an impermeable lid and a line for measuring liquids. It is made from EarthFirst® natural resources and does not contain BPA and BPS. The 63mm lid can be combined with other wide bottles from Nalgene.