...ounting Brackets. To mount to the PL11 Back-connecting Socket, use the PHC-5 Mounting Brackets. 61F-03B, -04B To mount to the PF113A-E Track-mounted Socket, use the PFC-A1 Mounting Brackets. ...

https://www.ia.omron.com/data_pdf/cat/connectionsocket_ds_e_4_1_csm13.pdf

...Electrode connection terminals 61F-04B Electrode connection terminals Use in conjunction with a 61F-03B/04B Surge Suppressor Unit in environments exposed to surges. Install the Surge Suppress...

https://www.ia.omron.com/data_pdf/cat/k7l_n211-e1_6_6_csm1050158.pdf