This was only available as a top tier reward in one of the events. Can't remember which one off the top of my head. Not possible to earn now.
Sporaek's Revenge or The Vanished Paladins But percentage eq are generally bad because they rely too heavily on how many troops you have instead of being a static number. But some people enjoy them. I'm in the static > percentage group though. edit:In short, you'll rarely find the eb anymore and the grind to get the boots are not worth the worry.