Our unique dual function push-pull design is the ideal product for your space, combining two motions in one beautifully designed machine. Simple changeover adjustments make the DF-307 Assisted Chin-Up/Tricep Dip easy and comfortable to use. Chin-ups work your back muscles, the back of your shoulders and arms. Dips work the pushing muscles in your arms, the front of your shoulders, and offer some chest involvement.