What size are the knock outs on these? If you are going to "Romex" some in pair together you will need a way to secure the wire.

Flycool737, thank you for your question. We use a strain relief to secure the romex. If you look at the 5th picture on the Lowes page it will show you. If you have any other questions, please give us a call between the hours of 7 AM – 8 PM Central Standard Time, Monday thru Friday at 1-800-654-8483, press option 4