It contains: 1x38mm branch, 1x38mm hose length (these are pre-connected), mallet, jemmy bar, hydrant wheel, booster cabinet key, coupling keys, short line, reflective door tags, torch.. Thats all I can think of off the top of my head, basically everything and anything that you could need to gain access inside a building and get the internal hydrants to work. I'll try to get in to take some pictures shortly.
They are kept in a standard CFS canvas duffel bag the same as blankets or general purpose rope.
They aren't used in action as 'high rise' kits that often - due to the lack of high rises that burn around here. They are used for alarm calls in buildings where we have internal hydrant fittings, pillar hydrants located close to entrances or where there is a decent trek from the appliance to the entrance point of a structure. They are great for houses with long driveways etc etc.
The basic premise when used at a domestic job is that it allows the BA operators to carry their initial attack length with them to their entry point, so they can get set up and be ready to enter once the hose lay is completed. It's a waste of time with short driveways and normal suburban building placement, but when you have a long long driveway and restricted access for a large pumper, then it can be a godsend.