Original hueco board and bäm! board
Rob Candelaria was one of the first climbers to create a finger strength training tool for climbing.
This video gives a little history behind what was likely the first hangboard before diving into a twist on hangboarding based on scientific studies on max weight and minimum edge depth hangs in addition to the training principles of specificity and progressive overload.
The bäm! board is a wood, adjustable hangboard that allows you to set the edge and pocket depth anywhere between 3.5 and 0.5 cm and set the sloper angle in 5 deg increments from 15 to 50 deg. The goal of this board is to create a tool that allows for small increments of change to open and closed hand grips so you can slightly increase the difficulty as you get stronger.
Original hueco board and bäm! board from bam climbing on Vimeo.