Hello, this is going to be a very niche part but thought Id share in case someone needs this. 

This is part XB-2 for Bandai Gundam Wing Mastergrade kits. This is the part that is part of the shoulder joint and can break if you are too rough with the arms.

Fits the following mastergrade kits as that all share a common inner frame. 

• Deathsythe
• Deathsythe hell
• Heavyarms
• Heavyarms Custom
• Sandrock
• Sandrock Custom
• Shenlong
• Altron

NOTE: Because these kits are snap fit, they have a very tight tolerance to be snug, but also move freely. 3D printers are great but they are not the best at tight tolerances. As a result of the variations in printers and very tight tolerances, this part is likely not going to be a drop in fit. 

You will likely have to print a couple of these at various % increases to get just the right fit. Some sanding of filing of the part may also be needed to get the fitment just right. 

I have used this to fix the shoulder joint on a broken kit and can attest this does work as a replacement. 

Please print at 100% infill so its a solid part, its very small so the material usage is extremely small.