I've been using this shaker for a few months now, and I've regretted buying it since day 1. First off, "Flip-n-sip" is misleading. It's one or the other. If you use the straw, you can't "sip." To close the straw lid, you have to either remove the straw, or push it down inside your drink. There is nothing even remotely convenient about the straw. But this is nothing compared to the worst of this cup. It leaks SO bad, and it has from the beginning. The lid is extremely finnicky to put on and will not seal properly. But you won't know that when you put it on and tighten it. It will feel nice and straight. It will look good. But when you either shake it, or start drinking is when you find out by being covered in whatever contents you have in your cup. My advice: DO NOT WASTE YOUR MONEY ON THIS CUP!!!