Casio WM-320MT-N Waterproof and Dustproof Calculator Mini Just Type 12 Digits | eBay
CASIO WM-320MT: Water-protected calculator at reichelt elektronik
Dustproof and waterproof mini desk calculator CASIO General Calculators - Size: Mini just type, Mass (g): 175, Number of Digits: 12, Dust / Water Protection: IP54 | MonotaRO Singapore
Casio Waterproof Calculator for Dusty & Wet Environments | Octopus