Milwaukee M18 battery extension

This is an extension for the Milwaukee M18 battery.

You can double or triple the battery capacity from 1.5ah to 3ah or from 2ah to 4ah or go higher from 5ah to 7.5ah or 9ah. 

• 19mm is double the capacity
• 37mm is triple the capacity
• 55mm is four times the capacity

Video how it is working: https://youtu.be/-H1lXuREmdg