The housing made of ABS* to protect the I/O Terminal PCB (circuit board) from damages.
The holes are precisely cut for SIM reader card and USB socket .
The housing is made for owners of the I/O Terminal with ANS5 & ANS6 hardware
On the below photo is shows blue box with properly mounted ANS6 hardware inside.
* Acrylonitrile butadiene styrene (ABS) is a common thermoplastic polymer