The Eerder Full Metal Tubes fit the Xplorer luggage frame by Trigo/Valeria and the Brompton T bag luggage frame (40cm wide, 30cm tall). The 260 mm long tubes can be cut down for smaller (less tall) luggage frames if you like.
Most of the load in your Eerder Xplorer bag or any other Brompton bag is taken by the two vertical tubes in the luggage frame. The two tubular sections on the side don't do much for vertical loads as they pivot freely around the lower connection. So not a bad idea to replace them if you're a regular overloader, ie. carrying over 10 kg in your (Xplorer) bag.
Instructions: The more recent original Brompton frames can be taken apart without any tools. The vertical tubes can be taken out after carefully and evenly (both ends simultaneously) pulling out the tubular side sections.The bores in the plastic sections of the original Brompton frames are quite tight, so be carefull with taking it apart. Pushing in the Full metal Tubes can be a little tough. You might even need a plastic hammer (or hammer plus a block of wood for protection) to hammer them carefully into the plastic lower section.
For the Valeria by Trigo luggage frame which I supply with the Xplorer bag it's a little different. You need a 3 mm allen key to remove the four screw that hold the tubular side sections and you need a 4mm drill to remove the heads of the pop rivets that hold the vertical tubes. The vertical tubes can be taken out after evenly (both ends simultaneously) pulling out the tubular side sections. The fitment of the tubes is less firm than in the Brompton frames. So that makes is fairly easy.
There's no real need to put the pop rivets back in as the frame is held together by the bag. Hence Brompton doesn't use pop rivets anymore. You can put the screws back in to hold the tubular side sections, but also here not really needed.
What you get: one set of two 260 mm long tubes
Material: Cromoly steel 1/2" x 0.9mm seamless tube
Finish: matt black powdercoated in house on our solar energy
Hardware: nothing needed, just push or hammer these in
Weight: 137 gram (original aluminium tubes are 50 gram)
Load capacity: probably more than you can handle