SmartBells™ Ninja Mancuernas Ajustables de 40 kg
- Un par reemplaza 76 mancuernas, en incrementos de 1 kg
- Cada mancuerna equivale a 38 mancuernas en 1
- Entrena de forma más inteligente con incrementos de 1 kg
- Ajusta el peso de 3 kg a 40 kg
- Controladas de calidad y con 36 meses de garantía
- Moleteado de precisión para un rendimiento avanzado, mayor agarre y comodidad
Delivery and Shipping
Delivery and Shipping
We offer delivery to most EU countries. You can see a full list of delivery costs here. You can also check out our delivery FAQs here.
Why choose BrainGain
Why choose BrainGain
- FREE and fast delivery across Europe
- Rated EXCELLENT on Trustpilot
- Over 100,000 adjustable dumbbells sold
- Spread the cost with Klarna
- 3 year warranty as standard
Overview
Overview
Features
Features
Warranty
Warranty
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.
Product Highlights
Explore the key features of our SmartBells™ Ninja Mancuernas Ajustables de 40 kg by clicking on the pulsing highlights.
Your Body Is Already Losing Muscle
From age 30, your body naturally loses muscle mass. Without resistance training, it only gets worse.
muscle mass lost per decade from age 30. After 50, this accelerates to 1-2% per year.1
lower risk of all-cause mortality, cardiovascular disease and diabetes from strength training.2
per week is the optimal dose - just 3x 20-minute sessions for maximum longevity benefit.3
Built Different. Here's the Proof.
We surveyed 659 BrainGain customers across 5 key markets.
said the value justified the price or price wasn't even a concern.*
train 3 or more times per week with their BrainGain dumbbells.*
want to buy more BrainGain products (accessories, supplements, training).*
* Source: BrainGain Customer Survey, February 2026, n=659 across 5 markets.
Rated Excellent on Trustpilot
Don't just take our word for it. Over 1,800 verified reviews from real customers.
Really Happy!
Dean Moran
Really happy with these adjustable weights, easy to put together and smoothly changes weights from 2.5kg all the way up to 40kg.
I previously was using the 24kg
Lee Philpott
I previously was using the 24kg dumbells which are still going strong but have upgraded to the 40kg octagon dumbells, good quality dumbells and look amazing.
Great Quality 40kg Dumbbells
Stephen Hammond
They are great quality and very between 2.5 to 40kg. Perfect for my home gym setup. Quality and ease of use is 10/10 saves so much space and work really well for both me and my girlfriend.

DIMENSIONS
Nosotros vs. Otros
Ni exagerado ni sobrevalorado.
Solo mancuernas ajustables premium diseñadas para durar.








