BowFlex SelectTech 840 Adjustable Kettlebell
- Kettlebell
- 1
- Composite
- Black
- Better rated than 84%
- More reviewed than 92%
A space-saving kettlebell reviewers consistently praise for smooth, reliable weight changes, though the plastic housing and handle feel different from a traditional cast kettlebell.
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How it ranks among the 61 kettlebells we track
4.8★ across 7,600 Amazon ratings, Bayesian-smoothed toward the category average.
7,600 Amazon ratings, weighted on a log scale so huge counts don't drown everything.
2,000+ bought on Amazon last month.
Brand identity, imagery, description and spec coverage.
The ProductDome score is separate from the Amazon rating shown above: it combines the Bayesian-smoothed Amazon rating with evidence volume, tracked demand, and data quality across the 61 kettlebells we track - how the scorecard works · full kettlebells data report. Confidence: medium - useful but incomplete evidence.Last refreshed Jun 30, 2026. Data-computed, not a hands-on test. Compiled by the ProductDome Research Team.
Overview
The BowFlex SelectTech 840 is a single kettlebell that adjusts from 8 to 40 lbs by turning a dial, replacing six fixed kettlebells (8, 12, 20, 25, 35, and 40 lbs) in one compact shell.
The dial mechanism is the entire value proposition: instead of storing a rack of kettlebells, one unit covers a wide range for swings, squats, rows, and presses. Reviewers who also own traditional cast-iron kettlebells noted the plastic housing and thinner handle feel different from a solid kettlebell, though the weight-swapping speed makes up for it during a workout.
- Adjusts from 8 to 40 lbs via a turn-dial mechanism
- Replaces six fixed kettlebells (8, 12, 20, 25, 35, 40 lbs)
- Includes a 2-month trial of the JRNY mobile membership
- Compact, space-saving shell design
Who it's for
Fits home gyms with limited space where switching between exercises and weights quickly matters more than having a traditional cast handle. Less ideal for anyone who wants the exact grip feel of a solid kettlebell or who dislikes larger jumps between weight settings.
What buyers say
From Amazon customer reviews.
Reviewers repeatedly highlight how quick and secure the dial-based weight change feels, with several calling out the space savings compared to owning a full rack of kettlebells. The main criticism came from a reviewer who also owns traditional kettlebells and found the plastic housing and thin, smooth handle less premium, plus a bigger than expected jump between the 25 and 35 lb settings.
Strengths and trade-offs
Drawn from this product's published specifications.
- One dial swaps between six weights from 8 to 40 lbs
- Locks in securely with no wobble during use
- Saves significant space over a rack of kettlebells
- Plastic housing feels less solid than cast iron
- Handle is thinner and smoother, offering less grip texture
- Jump from 25 to 35 lbs is larger than steps around it
Performance notes
Turning the dial clicks the internal weight plates into place, which reviewers describe as fast, smooth, and secure with no wobble once locked. The jump from 25 to 35 lbs is a bigger single step than the increments below it, which one reviewer flagged as worth planning around if progressing gradually matters.
Specifications
| Brand | BowFlex |
|---|---|
| Model | 100790 |
| Dimensions & fit | |
| Item Weight | 40 pounds |
| Handle Diameter | 1.1 inches |
| Construction & materials | |
| Material | Composite |
| Color | Black |
| Included components | |
| Unit Count | 1 |
| Warranty & support | |
| Warranty Description | 2 years |
| Other details | |
| Item Type Name | Bowflex SelectTech 840 Kettlebell |
| Part Number | 100790 |
How it compares
This product against the closest alternatives we track in kettlebells.
| Product | Amazon rating | Ratings | ProductDome score |
|---|---|---|---|
| BowFlex SelectTech 840 Adjustable KettlebellThis product | 4.8 / 5 | 7,600 | 4.7 / 5 |
| Amazon Basics Cast Iron Kettlebell for Strength TrainingAmazon | 4.8 / 5 | 27,900 | 4.6 / 5 |
| Marcy Hammertone Kettle BellsMarcy | 4.8 / 5 | 2,300 | 4.5 / 5 |
| Yes4All Kettlebell, 5-100 LB Vinyl Coated Cast Iron Strength Training Kettlebells for…Yes4All | 4.8 / 5 | 25,200 | 4.5 / 5 |
| Tone Fitness KettlebellTone | 4.6 / 5 | 1,800 | 4.5 / 5 |
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Questions about the BowFlex 100790
Common buyer questions answered straight from the product spec data - no fluff, no "it depends".
What weight range does the BowFlex SelectTech 840 cover?
8 to 40 lbs, adjustable by turning the dial through six settings: 8, 12, 20, 25, 35, and 40 lbs.
Does the weight change feel secure once set?
Reviewers consistently describe it locking in with no wobble or shifting during swings, presses, or squats.
Is the handle the same as a traditional kettlebell?
Not quite; at least one reviewer who owns cast-iron kettlebells found the handle thinner and smoother, offering less grip texture than a solid kettlebell.