A dropped chain is one of the most infuriating and messy calamities that can befall a cyclist. Even the most well-adjusted drivetrain can lose its way, and when it does we will usually find ourselves grappling with chain and chainrings in the effort to get everything back in place. Our fingers are filthy, and very soon our handlebars will be too! This is where Rehook comes in.The nature of the chain makes it quite difficult to get hold of, and this is what prompted Rehook inventor Wayne Taylor to design a tool specific for the job. Taylor started designing and building prototypes very rapidly with a 3D-printing process, and was ready to test the market within just ten weeks. Sales have continued to grow, and Taylor now uses injection moulding for mass-production – opening the door to selling through retail outlets. The Rehook is very simple, and comes with an elasticated band so that it can be strapped to the frame – so that your other bike tools don’t get coated by chain gunk. It’s constructed from a single piece of injection-moulded plastic, yet weighs almost nothing – 18g. I was very impressed with the function of the Rehook. It holds the chain securely and you can pull the chain quite hard if it needs to be rescued from a wedged-in position. It is quite a good design approach to keep it mounted by itself on the frame, but personally I’d have gone for another approach: supply a cover for the “business end” of the tool so that it can be stashed where it really belongs, in the saddlebag.