I got this stretching device from Perform Better and, even though it's just a chunk of red plastic, I'm finding it to be very useful. For one thing, just owning it and seeing it sitting on the floor looking at me reminds me to actually do the stretches that I need so badly. It's easy to just feel like stretching is "extra" and put it off until later, then forget all about it. But the truth is that since I've had this great little chunk of red plastic, my back, knees, and hips have felt better than they have in years! Also, it's made to rock a little from side to side while you stretch, so you end up stretching muscles that usually don't get any action. It's true that you could just as well do these stretches using a block of wood or a rock or curb of the street, but the red plastic is just so appealing, right? Seriously, it actually is more effective with the Tri-Stretch.
The two main ways I use it are for my calf/ankle area and for my hamstring area. I'm insanely tight in these two areas and this leads to multiple problems in the knee, hip, and lower back areas. I start with the large gastrocnemius muscle in my calf by keeping my knees straight and leaning against a wall or car, whatever, with the non-stretching foot placed a little ahead of the stretching foot and pressing my heel of the stretching foot into the tri-stretch device. Turning the toes slightly in and stretching, then slightly out and stretching will hit all sides of your calf muscles in a great way.
Then I work into the soleus muscle, which includes the achilles tendon and ankle, by bending the knee of the stretching leg and continuing to press the heel into the tri-stretch device. Once again, turning the toes inward and stretching, then outward and stretching completes the stretch.
Moving on to hamstrings, just shift your stance so that the foot of the non-stretching leg is now a little behind the foot of the stretching leg. With knees unlocked but kind of straight, bend from the hips forward and stretch your hamstring. To deepen the stretch, reach down and hold the tri-stretch or your foot or ankle and let your head drop towards your knee. This opens up the back muscles and gives you a good stretch from your head all the way to your foot. As with the calf stretch, you can turn the toes inward and outward to hit many more areas of your hamstrings than you may be used to.