Hex dumbbells are the first bit of kit I bought for my home gym—here's why you should too

Two dumbbells with black hexagonal heads on blue exercise mat seen from above.

If you could only use one piece of fitness kit for the rest of your life, what would it be?

I recently asked this question to Cody Mooney of pliability and Luke Zocchi of Centr, two formidable athletes in their own right who have trained the great and good of CrossFit and Hollywood, respectively.