What’s the difference between the ECC-UHC and ECC-UMC Cutout Covers?
ECC-UHC - one cutout cover fits both porcelain and polymer cutouts

Installation instructions for the ECC-UH models
Most polymer cutouts install the pins in the lower two holes.
Porcelain cutouts install the pins in the front lower hole and the top back hole.
See the pictures above.
Cutout Cover ECC-UHC-FR
The ECC-UHC-FR is molded with cruciforms for the capability to add an extension to the front of the cover for added coverage.The extension can be ordered separately or with the ECC-UHC. Part number with the extension would be ECC-UHCE. Flame retardant, FR UL 94 5VA.
ECC-10UC - one cutout cover fits both porcelain and polymer SMD-20 cutouts

SC-1
Squirrel cover, for use with ECC-UHC and ECC-UMC cutout covers. The squirrel cover can be hot stick installed. Covers the slot in the back and up over the top of the cutout cover to help prevent squirrels from storing nuts inside the cutout cover. Available in FR, UL 94 5VA. Part number would be SC-1-FR when ordering separately. US Patent 10,566,166
SC-1-FR
Squirrel cover FR rated, for use with ECC-UHC-FR and ECC-UMC-FR cutout covers. When ordering the cutout cover and squirrel cover together part number would be ECC-UHCS-FR or ECC-UMCS-FR. The squirrel cover can be hot stick installed. Covers the slot in the back and up over the top of the cutout cover to help prevent squirrels from storing nuts inside the cutout cover. Part number would be SC-1-FR when ordering separately.
US Patent 10,566,166