There's not much to say about this item. As can be seen in the pic, it's a solid piece of metal with six tools along the edges. Does an effective job at basic roadside repairs, although you won't have every size allen bolt you need, particularly if you're on the road with your kids and their bikes along with your own. Also the length of the item can get in the way of screwing or unscrewing a bolt - meaning you might only be able to turn the bolt 20 degrees at a time. That being said it's a quality, reliable, simple tool and I expect it will last a lifetime.
You will need this tool to install your cassettes. The updated version with the guide pin makes the tool foolproof. Improvement on an already great design. Made in the USA too! Whats no to like!