Telesin sent me an awesome product, its name is “Allinbox” and allows you to charge two Canon batteries at the same time and acts as a reader for SD memory cards. Allinbox is compatible with 5D Mark II III, EOS 5D Mark IV, 5DS, 5DSR, 6D, 60Da, 7D, 7D Mark II, 70D, 80D batteries.
This product is very useful for photographer like me because we need to load batteries as fast as possible.
It is available the Canon batteries version but soon will be released for Sony and Nikon too.
You can buy this brand new product on Amazon.