Addendum - contents of the bag:
- Sea & Sea housing for Nikon Z6/Z7
- 230 mm Zen dome port
- 40 mm extension ring
- Macro port
- Nikon Z6
- Nikon Z7
- Nikon 8-15 mm fisheye
- Nikon Z 14-30/4
- Nikon Z 24-70/4
- Nikon 105 mm macro (F-mount)
- Nikon Z 40/2
- FTZ adapter
- Lots and lots of batteries, for strobes, camera and focus light
- Vacuum pump and some other small stuff
- Uh... the taxfree candy I couldn't fit in my shoulder bag
The total weight of 15 kg or slightly more isn't terribly much to lift in itself but the design of the bag made it feel very heavy to carry when wandering the airports.