Bowflex SelectTech 840 Adjustable Kettlebell Review

The SelectTech 840 does for kettlebells what the 552 does for dumbbells: packs several weights into one unit you adjust with a dial. Six settings cover 3.5 to 18kg, the weight plates inside are cast iron, and the change takes about two seconds. For a home gym short on space, that convenience is the whole appeal.

The problem is the shape. To house the mechanism, the 840 has a wide plastic base and a handle that reviewers repeatedly single out as awkward, so it never quite feels like a real kettlebell. It is a genuinely useful tool for pressing, squats and carries, but if your training is built on high-rep swings and snatches, a solid cast iron bell will serve you better.

A single dial on the base selects the weight. You set it down, twist to the number you want, and lift: no plates to swap, no tools, a couple of seconds at most. This is the fastest weight change of any kettlebell we cover, and it is ideal for circuits where you drop from a heavy set to a lighter one without pausing.

The trade is the spacing. The six settings are 3.5, 5.5, 9, 11, 16 and 18kg, which are uneven: fine at the bottom for pressing and rehab, but with a big jump from 5.5kg to 9kg and then to 11, 16 and 18kg. For progressive swings where you want steady 2kg steps, the Stealth with its even 2kg increments is the better tool.

This is the part to understand before buying. A traditional kettlebell is a single casting with a smooth arc of a handle and a compact ball. The 840 has to hide a dial mechanism, so it carries a large plastic base that sits wider and squarer than a cast bell, and the handle is shaped around that housing.

Men's Fitness UK, among others, found the ergonomics the weak point: the handle feel and the bulk of the base make it less pleasant on the high-rep, re-gripping movements kettlebells are best known for. For goblet squats, overhead presses, rows and loaded carries, none of that matters much. For long sets of swings or snatches, it does.

Great for

• Small home gyms that want several kettlebell weights without a rack
• Training built on presses, goblet squats, rows and carries
• Circuits where fast weight changes matter more than feel
• Beginners wanting to find their working weight before committing to fixed bells

Not for

• High-rep swings and snatches, where feel and a real handle matter
• Anyone who wants to drop the bell (buy solid cast iron)
• Lifters who swing above 18kg
• Buyers paying full RRP: fixed bells are better value at that price

The SelectTech 840 is the most convenient adjustable kettlebell you can buy: six weights, a two-second dial, a compact footprint. If your kettlebell work is presses, squats, rows and carries, and space is tight, it earns its place, especially at its frequent discounted price. But the plastic base and the handle keep it from feeling like the real thing, and it cannot be dropped. For swings-first training or the best feel, the cast iron Attack or Stealth bells are the better buy.