This case fits HRD-B3X module with 4000 mAh battery. The dimensions of the case are 67 mm x 100 mm x 22 mm. It consists of two parts (a base and a lid) and is designed to be glued together. It is fully covered with two cutouts for charging cable and microUSB port.

Recommended print settings

• layer height: 0.2 mm
• perimeters: 2
• solid layers: 5
• infill: 20% grid
• supports: no

Assembly instructions

1. Insert battery.
2. Insert HRD-B3X board. Place microUSB input into rectangular hole.
3. Pass the charging cable through the round hole. Connect it to the board.
4. Put the lid on. The lid should be glued to the case.

I additionally used hot glue inside to keep everything together.