What do they do? These accessories simply let you do press-ups without straining your wrists. They develop your upper body, pecs and triceps, as well as your abdominals and back.
How do I choose the right ones? There aren't many models available so the choice is fairly easy. However, make sure your push-up bars aren't too hard on your palms and check they're stable enough (they should grip the floor well).
How often should I use it? If you're a beginner, do press-ups on your knees so you put less weight on your arms. If you're experienced, place the tips of your toes on the ground, making sure not to arch your back. Your muscles need time to recover so don't do more than two sessions of press-ups per week.
Available from all good sports shops, around £10.