In anticipation of needing a portable, non-spill beverage container on the trip to Shenandoah National Park, I picked up this Thermos brand tumbler to keep cold water at the ready. Thermos is a brand that's always been reliable ever since I was a kid, and I liked the looks of it.
This item has a screw-off lid with a lever on it that opens and closes the drinking slits. On the underside of the cap there is a rubbery plastic expanding flange that seals it tight. The Thermos keeps drinks cold for 18 hours, or hot for 7 hours. It's double walled so there's almost no heat transfer in or out. Inside is stainless steel. It's just the right size for a bike cup holder, and although it bounced around a bit in my plastic holder, it was never at risk for falling out. And boy did it come in handy on the trip. Anytime I needed cold water, it was right there, ice cold. It holds up to 16 ounces. I never had to worry about it spilling out, and it was easy to get a quick sip with a flip of the lever.
It comes in 12 different exterior colors including stainless, and oddly the price varies by color. So I took the midnight blue option which was good looking and middle priced. It even has a tea bag hook in the cap if you want to brew tea.
This is one puurchase with which I am very pleased. Highly recommended.