40kg SmartBells™ Ninja Adjustable Dumbbells

Our 2026 SmartBells™ Ninja are our most advanced adjustable dumbbells.

One compact pair replaces an entire rack of 76 dumbbells.

Fast-change from 3kg to 40kg in 1kg increments. The Ninjas deliver 38 exact weight settings that can be cycled through in under 1 second, giving you total control over your strength-training goals without breaking your workout rhythm.

Eliminate downtime changing weights between sets and unnecessarily large jumps between weights when doing progression.

Matte steel plates provide durability with a refined finish. The brushed aluminium handle is ergonomically shaped with precision knurling for controlled grip under load. A patented safety-lock mechanism secures only the selected weight, while the steel base ensures stability at rest.

The Ninjas are designed for lifters who want to Train Smarter.

3kg–40kg in 1kg increments: 38 precise weight settings for controlled progression. Weight increments include: 3kg, 4kg, 5kg, 6kg, 7kg, 8kg, 9kg, 10kg, 11kg, 12kg, 13kg, 14kg, 15kg, 16kg, 17kg, 18kg, 19kg, 20kg, 21kg, 22kg, 23kg, 24kg, 25kg, 26kg, 27kg, 28kg, 29kg, 30kg, 31kg, 32kg, 33kg, 34kg, 35kg, 36kg, 37kg, 38kg, 39kg, 40kg.

Equivalent to 76 dumbbells per pair: Full rack capability without the space requirement.

Fast twist-handle adjustment: Change weights in seconds without interrupting your workout, with intelligent patented engineering.

Integrated safety-lock system: Only the selected weight is engaged for secure lifting.

Steel plate construction: Durable design built for long-term use.

Brushed aluminium knurled handle: Secure grip with a balanced, comfortable feel.

Stainless steel base: Stable foundation designed for heavy use.

All of our products come with a 3 year warranty as standard. During the warranty period we will repair or replace, at no charge, products or parts of the product defective because of improper materials or workmanship, under normal use and maintenance. Full Warranty Information can be found here.