**The Ab Wheel of Torture!! I have a love-hate relationship with them, but it is the BEST piece of equipment you can buy for rock hard abs, and they are very inexpensive!**
The Ab Wheel is one of the best, simple pieces of exercise equipment available. I love mine, it works your abs, core, shoulders, back, and triceps all with one simple (not easy!!) exercise. It's cheap, nearly indestructible, and highly effective!! Buy at your own risk---your body will be sore if used properly!