This Smart Buckle turns your classic watch into a handsome fitness tracker

If your grandfather wasn’t too impressed when you swapped the family Seamaster for a plastic fitness band, this could be your ticket to getting back on good terms. The Smart Buckle (from $39) is basically a Fitbit-in-a-watch-clasp, promising to connect to most 20mm watch bands (or its maker’s own silicon and leather straps). It tracks all the usual steps, pace, calories, distance and sleep, and apparently lasts a week on a single charge. It’s also waterproof, should you actually take your sailing watch onto the high seas (or, more likely, get caught in some sideways British rain).