There are some photos on Leo's
website and a couple of pages for flying them today Vashon story
The very first rocket I had was a coldpower Marauder and have recently bought a Yankee 5 set (but only to collect) and would love to get a Marauder set if one came up at a sensible price, purely because it was my first rocket.
The equivalent power of these motors is about a B, thought the motor is a lot heavier than a BP B motor. From my flights in the dim and distant past they are not very efficient and can be tempramental, and also you launch from about 3 feet away so don't really get to see that much of the flight. That said they are a very different style of flying from BP motors and could make a nice change from standard flying.
I'm guessing that you are looking at the motor on e-bay. Looking at the post it is used and incomplete. The missing parts are the ejection piston (part BT-50 coupler and part plastic moulding and a spring) and the filling hose and valve. Nothing insurmountable there but certainly not a case of slip it into a model and it is ready to go. Given these motors are about 30 years old I would wonder what condition the rubber seals and grippers are in, nor how they could be replaced. Conversely, these come up very rarely in the UK so could be worth a look if the price is low enough and you are prepared to do some research on these motors and work on it.
Happy bidding and flying