Jay Cutler is known for using these dumbbells, which are called J*Bells.
They bring the center of mass to the middle instead of the loading of a typical dumbbell.
For a set of the J*Bells (3kg-18kg) they’re $18,000.
Fatbells and CMB’s offer similar functionality for less.
Video
Jay Cutler (@mrojaycutler)
These dumbbells are wild
Video
— https://nitter.net/mrojaycutler/status/2055904806792048642#m