Onyx Adjustable Water-Filled Medicine Ball

Onyx Adjustable Water-Filled Medicine Ball

One Ball. Every Weight From 3kg to 20.5kg.

A full slam ball progression costs hundreds of dollars and a rack to store it. This is the alternative: one ball whose weight you set with a tap. Empty it's 3kg for warm-ups, beginners and rehab; fully filled it's a 20.5kg heavy ball for serious strength work - and every weight in between is just a fill level. One tool, every user in the gym, one spot on the floor.

The water does something a fixed ball can't, too: it shifts as you move. Every slam, throw, twist and carry has live, moving resistance inside it, forcing your core and stabilisers to fight the slosh - the same principle behind unstable-load training used in athletic conditioning.

The unique 122-sided textured surface keeps grip locked in through sweaty, high-intensity rounds, and the non-bounce design is engineered for slams, wall balls and functional drills.

Key Features

• Adjustable weight: 3kg empty to 20.5kg full - set it by fill level, change it in a minute
• Shifting-water resistance - live instability that works stabilisers a fixed ball never touches
• 122-sided ergonomic texture - sweat-proof, anti-slip grip for confident slams and throws
• Non-bounce design - built for slams, wall balls, throws, twists and presses
• Replaces a whole rack - beginner to advanced progressions in one ball
• Ideal for HIIT, CrossFit, core work, rehab and group classes

Frequently Asked Questions (FAQs)

Q: How does it compare to a normal slam ball?
A: A fixed slam ball is one weight forever - to progress, you buy another ball. This adjusts from 3kg to 20.5kg with water, and the shifting fill adds a stabiliser challenge fixed balls can't replicate. One ball does the work of a full progression rack.

Q: How do I change the weight?
A: Add or drain water through the fill port - a minute at any tap. Part-filled weights feel the most "alive" as the water moves; fully filled it behaves closest to a solid heavy ball.

Q: Is it suitable for slams?
A: Yes - the durable shell and non-bounce design are made for slam work on gym flooring. Like any dead ball, slam onto rubber flooring rather than bare concrete for the longest life.

Q: Who is it for?
A: Everyone from rehab patients (light fills) to advanced athletes (full weight) - which is exactly why PTs, group-class studios and home gyms love it: one ball serves every client.

Backed by Fitness Hero Sydney

Stocked at our Sydney warehouse with local warranty support - and you can see the range in person at our Bankstown Megastore.

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3 to 20.5 kilos from one tap - the last medicine ball you'll need to buy.