About 1990-91 (judging from the FCC ID info) a three button clear mouse branded LEVEL was produced by a Taiwan company, Midasonic Industrial. The completely clear case allows full view of the green circuit board and the ball from all sides.
The LEVEL clear mouse is a medium sized mouse with a serial interface and a switch on the bottom for PC or MS protocol (Mouse Systems (3-buttons) or Microsoft (2-buttons)). A small round button on the left side where the thumb rides provides speed control for the mouse pointer. In Windows the four speeds go from very slow to probably too fast, covering the whole screen for one inch movement on the mouse pad. The action likely varies per computer.
Clear LEVEL mouse by Midasonic
The identifying aspects of its label read simply:
FCC ID: G7A3HSF860 No. 355612