Meet the Two Stones Portable Fingerboard: a portable climb training tool that you can use anywhere to strengthen your fingers. It is CNC milled from wood and weighs only 1.65 pounds. It comes with 4 different depths pockets and edges to simulate various holds.
You can use this fingerboard to strengthen your grip, wrists, hands, and arms. You can use this on pull up bars indoors and outside to exercise. You can find out more here.