Here is a handy tool that lets you stretch your hamstrings and calves more effectively. The IdealStretch can also be used to relieve tension in your back and knees. It can be used before and after workout to stay injury-free and recover from tough workouts.
IdealStretch lets you stretch your hamstrings and hips while lying on your back. It also helps align your body. When done, you can divide it in two and fit it in your bag.