Our hot tub with outside firewood heater basic set already includes:

firewood stove (ISIS 304 metal mark);
insulated spa hud;
water outlet outside;
foam insulation;
2 metal straps;
chimeney 2m;
chimney protective;
stair steps;
outside decorative spruce wood,
wooden paddle (if no air system)

Also you can upgrade hot tub with extra comfort options.