Kettlebell training has a space problem. You need multiple weights to progress, and those cast-iron lumps take up a corner of the room. Bowflex solves this with the SelectTech 840, an adjustable kettlebell that packs six different weights into one compact, composite shell. Turn the dial to select from 8 to 40 pounds in even increments. It replaces a rack of kettlebells with a single unit that fits on a shelf.

The mechanism is simple and reliable. A dial on the side clicks into your chosen weight, and the internal plate system locks in place. It feels solid during swings and clean-and-presses, with no wobble or shifting. The 28mm handle diameter is comfortable for two-handed swings and fits most hand sizes. The composite material has a slight texture that provides grip without tearing up your palms. At 40 pounds, it handles ballistic movements and goblet squats well, though serious kettlebell users will want heavier options.

The included JRNY app membership adds motion tracking for form feedback, which works best when you have your phone propped at the right angle. The battery-free design means you never charge it, and the weight selection is fast enough to flow through a circuit without interruption. For home gyms tight on space, this is a practical solution that gets the job done without compromise on feel.