I bought the SPORTS CAP top for my S'well Bottle and it works great. Unfortunately you have to use your fingers to push the spout to open or close it or use a handkerchief or napkin so your fingers won't touch the top. I wouldn't use this is the gym. 

Another issue is that if you put your bottle with this cap inside your bag make sure it goes into a slot so the top of the bottle will remain upright and preferably sticking out of the top of the bag. I put mine in my tote for school and somehow something pressed on the top so it opened up and water was leaking out and covered my papers and notebook. I don't know what it was that pressed up against it in order for it to open but it did. This also happened to a classmate of mine who bought this cap. 

So for commutes and in bag carry of my S'well bottle I went back to the screw on tops. I'll use this cap on the bottle in the car that's in the cup holder but I won't take a chance otherwise.