You can find good ones at most feedstores- horsetack, farm supply outlets. It looks like a big plier, with a hammer on one jaw and a big claw like marlinespike on the other.
There are two sets of notches below the jaw's 'mouth' for crimping and a cutting surface for snipping 'bob war.'
They have a VERY romantic name not commonly heard outside of farms and ranches- we call them fence pliers.