A brake (or riving brake) is used in conjunction with the froe so I thought it would be apropo to mention it here. I have heard of these also being called a “cleave”.
there are several types:
see Peter Follansbee’s blog and The Barn on White Run
horizontal or box like
see Peter Galbert’s blog
on Jennie Alexander’s Greenwoodworking blog
and one that is a sort of sideways fork.
see”The Woodwright’s Shop” by Roy Underhill
made from a tree fork.
They all get used similarly; you prop your piece to be split in the gap (after you have started the froe into the end) and push down on the thicker side of the split. Go slowly and watch incase the split wants to run one way or the other. this way you can get your weight into it without straining too much.
You need one, mine is like the boxy one. but don’t get carried away and make all of them 😉