Siemens SIMATIC HMI IFP Operating Instructions Manual page 124

Markings and symbols
B.1 Safety-relevant symbols
Symbol Meaning
Only for industrial applications and indoor areas (control cabinet)
Install in control cabinet only
Devices approved for Ex Zone 2 in a control cabinet with min. IP54
Devices approved for Ex Zone 22 in a control cabinet with min. IP6x
124
Reference
IFP, IFP PRO, IFP ETH
Operating Instructions, 09/2019, A5E31298376-AJ