Kettlebells: cast, competition and adjustable designs
Compare the shell shape, handle opening and loading method before buying a single bell or a progression of weights.
A kettlebell places most of its mass below a loop-shaped handle. Its shape matters as well as its weight because the bell can pass between the legs, rest against the forearm or move overhead. Choose a design around the movements you intend to practise.

A fixed 16 kg bell cast as one piece, with a flat base and powder-coated handle. Its body diameter is 15.5 cm; other weights in the range change size.
Photo: SMAI.The main types
Conventional cast bells normally change dimensions as their weight increases. Competition-shaped ranges keep the outer dimensions consistent while changing how much material is inside. An adjustable model changes its internal load, although some designs use an external plate stack rather than a closed shell.
Those categories do not tell you the material automatically. SMAI’s current competition listing describes a hollow cast-iron shell; Bells of Steel specifies a steel shell with removable iron plates. A word such as competition also does not establish acceptance by the organiser of your particular event.
| Design | Useful characteristic | Compromise |
|---|---|---|
| Fixed cast bell | Simple, complete weight with no adjustment | Size changes across the weight range |
| Fixed competition shape | Similar external geometry at different loads | Large shell even at a lighter weight |
| Adjustable closed shell | Several weights share one outer shape | Internal loading and locks take time to change |
| External plate-loaded handle | May reuse compatible weight plates | Plate stack changes clearance and contact surfaces |
Sources: SMAI: cast-iron kettlebell range · SMAI: current competition kettlebell · Bells of Steel US: adjustable kettlebell and package inventory
Check the handle and the bell together
Grip diameter is the thickness of the handle. The window is the opening inside it. They answer different questions: whether you can close your hand comfortably, whether two hands fit, and where the bell can settle against the arm. A large window is not always preferable if it changes the position you are practising.
For a showroom comparison, use the same intended movement with each shape. Consider the transition into the rack position, clearance around the wrist and room for both hands during a swing. Do not assume that a bell sold as 16 kg has the same body diameter, height or handle as a competing 16 kg model.
Sources: SMAI: cast-iron kettlebell range · SMAI: current competition kettlebell · Bells of Steel US: adjustable kettlebell and package inventory
One weight rarely suits every exercise
Choose the initial weight from movements you already perform competently or under instruction, rather than buying a universal “men’s” or “women’s” size. A weight suitable for a two-handed lower-body movement may be excessive for a one-arm press. A heavy purchase that cannot be controlled is not a useful way to make the collection future-proof.
For two-bell exercises, confirm that the order contains a pair and that the two bells have compatible shapes. If several people share the gym, fixed bells let them train at different weights without opening an adjustable shell between users. If storage is tight, an adjustable model can make several modest increments available in one footprint.
Sources: SMAI: cast-iron kettlebell range · SMAI: current competition kettlebell · Bells of Steel US: adjustable kettlebell and package inventory
Adjustable packages and Australian buying routes
Read the inventory, not just the maximum advertised for the product family. A base adjustable package can include less weight than the optional expanded version. Check the unloaded shell mass, included plates, fastening tools and all attainable configurations. The shell alone may already be heavier than the minimum you need.
SMAI and Iron Edge list fixed bells through Australian stores. The Bells of Steel model included here is a design reference from its US store, so its US price, shipping offer and warranty route cannot be treated as an Australian landed quote. Compare the whole delivered order when deciding between a local fixed set and an imported adjustable.
Keep locking hardware and adjustment instructions with an adjustable bell. Inspect its assembly whenever the internal load changes. For any design, choose a storage position where the handle is easy to reach and the bell will not become an obstacle beside the bench or doorway.
Sources: SMAI: cast-iron kettlebell range · SMAI: current competition kettlebell · Bells of Steel US: adjustable kettlebell and package inventory · Iron Edge: Pro Grade kettlebell
Models mentioned in this article

SMAI Cast Iron Kettlebell — 16 kg
A straightforward bell for swings, carries and goblet work when 16 kg suits the exercise. The handle is shaped for two-handed use.
Specifications & buying options
SMAI Competition Kettlebell — 16 kg
Choose the consistent shell size if you plan to practise with several weights and want the bell to sit similarly on the forearm.
Specifications & buying options
Bells of Steel Adjustable Competition Kettlebell — 12–20.5 kg
One shell can replace several fixed kettlebells where storage is tight. The included half-kilogram plate is useful for smaller increases without another complete bell.
Specifications & buying optionsSources & further reading
Checked 17 Oct 2026. The links below identify the sources used for this article.