The Pull Block is designed for climbers looking for precise edges they want to train on.  Small, drops in the bag and goes to the gym or the crag.  Run your choice of cord through it and add your weights to build the grip strength plan you need.  Even more importantly, you can custom build the block to have the range of crimps you want to train on.  Designed in OnShape, a free and online CAD software, you can open the SolidWorks model on many CAD programs and adjust the parametric settings to the edges you specifically want to train on.  Even open it in OnShape and export it from there.

  Select the four edges you want to train on, export the model to your slicer and print. Or use the 3MF I have already built with the default edges of 20mm, 16mm, 12mm and 8mm, the last having a slight incut.  I've also attached a block using smaller, Advanced difficulty edges, and another with larger edges for the newer climbers.

  The block has 8.5mm holes on either end for your choice of 8mm or less cord, or doubled up paracord if that's what is handy.  Use it to warm up at the crag, gym, or for dedicated grip training sessions. Print two of them and hang them from your pullup bar as a small hangboard.  The options are out there and when you''ve progressed beyond the edges, adjust them and print a harder one.  

  Good luck on the sends out there.  Comments, critique, requests welcome.