Klean Kanteen offers a range of stainless steel water bottles that are well made, relatively lightweight, and come with a variety of interchangeable tops. They seal tightly (I pack them in my briefcase with my computer), even with the sport top. They’re light enough to compare well with a plastic water bottle, but without the ecological waste of disposable bottles or the odor of reusable plastic bottles.
They come in various sizes (12 oz. to 40 oz.) and the 18 oz size fits nicely in a bicycle bottle cage. I take mine through airport security empty and fill it on the other side.
[The new Sport Cap 2.0, a sport cap perched alongside a loop, is a particularly cool and functional design. I prefer them to Sigg bottles (previously reviewed) for the simplicity of the Klean Kanteen's design and many cap options -- each member of my family uses a different one. Also, it turns out some older Sigg bottles contained BPA, though the company initially claimed otherwise. Klean Kanteen’s bottles are 100% 18/8 stainless steel -- they even have a stainless steel cap option now -- and there’s not any doubt about their safety. --es]