We use the Decora plate inserts to facilitate keystone addition to all FSR wall boxes, floor boxes and raceway.
These will accept any keystones and you will find the following on our store
CAT 6 unshielded – https://shop.dizzyfish.net/product/cobi-cabling-c11-6000-cat-6-unshielded-keystone-copy/
CAT 6 Shielded – https://shop.dizzyfish.net/product/cobi-cabling-c21-6000-cat-6-shielded-keystone/
CAT 5e – https://shop.dizzyfish.net/product/cobi-cabling-c11-5000-cat-5e-shielded-keystone-copy/
CAT 6a shielded – https://shop.dizzyfish.net/product/cobi-cabling-c21-1001-cat-6-unshielded-keystone-copy-2/
F connector – https://shop.dizzyfish.net/product/black-f-connect-keystone/
HDMI – https://shop.dizzyfish.net/product/hdmi-keystone/
Blank Keystones – https://shop.dizzyfish.net/product/black-keystone-blanks/