That's when I came across the Safe Sippy2 by Kid Basix!
If you're using a plastic sippy, you might not like that you can't easily see how much liquid is left inside. With stainless steel there is no way around this, but it's a small price to pay for being way healthier. With experience, you'll be able to gauge how much is in there simply by picking it up and giving it a little shake. Until then, you can quickly unscrew the top, peek inside, and screw it back on. Takes all of 3 seconds.
I have to add that I love the statement on the box warning that giving drinks other than water at non-mealtimes and in bed can lead to childhood tooth decay. Go Kid Basix!
If you can't wait to get your hands on this cup, you can order one on Diapers.com for $15.99 - there are several fun colors to choose from! If it's your first order, get 20% off with discount code "MINYMOE" :)
You can check out the other Kid Basix products, including the Safe Starter (for babies - with a proper baby bottle nipple), Safe Sippy (like the Safe Sippy2 but doesn't convert), and Safe Sporter!