I have used this in my 2-stage Mongoose with a B6-6 for a pretty spectacular flight. I prefer to use this over C6-0s so you can see the staging occur closer to the ground. It also makes finding your booster easier. Before launching a 2-stage rocket make sure you always have someone track the booster all the way to the ground.

Great Booster stage engine for smaller 2 stage rockets. Lets you actually see deployment of the first stage (which is why I launch 2 stage rockets). If pure altitude is your goal go with the C6-0s but for pure fun, these are great.

I like 2 stage rockets, but I can't always find a field big enough to fly them in. Using a B6-0 in the booster instead of a C6-0 changes the flight enough that I can fly on a smaller field. Just have to make sure that it has enough boost to get the rocket moving off the pad fast enough.