All the boxes are 3D printable using small hobbyist machines. We have had success printing in PLA and recommend the Bio PLA UK from 3DTomorrow.
An STLs pack is available for a small cost and a print service is available.
The Hub Case take the custom designed PCB on which is mounted the NodeMCU, I2C Multiplexor and SD Card Breakout. In addition the battery is located under the PCB with a Power Charging board neatly slotted into the side.
Mounted externally this case allows sensors to be sited outside the test location for comparison. There are 2 and 3 sensor options for the back piece. The top piece is available both blank and with an UV/Light sensor option (shown).
The internal cases come in 2 and 3 sensor types with options for front and rear venting.