The Optimum Nutrition Smart Shake is the ultimate gym companion. This shaker has two detachable compartments for storing your nutritional supplements in. The main compartment is 700ml and has a mixing grill to break up any powder clumps and there is also a storage section in the bottom which you can use to store extra powder or pills.
You might have your pre-workout in the top and sip on it as you drive to the gym then have your protein powder in the bottom ready to go post-workout.
No need to carry 2 different shakers-this smart shake does it all in one.