Junction Box with Knockouts JB-3957-KO - Bud Industries
IP68 Dust and Waterproof Screw Cover Boxes with Knockout | Etan
Carlon 6 in. x 6 in. x 4 in. Gray PVC Junction Box E987RR - The Home Depot
TayMac 1-Gang PVC Weatherproof New Work/Old Work Switch/Outlet Electrical Box in the Electrical Boxes department at Lowes.com
Electrical Box, PVC, 8-5/8x8-5/8x4 in. - Electrical Boxes - Amazon.com
Surface mounted junction box - IP54 - IP65, -5 °C ... +60 °C | SAFYBOX CE - Uriarte Safybox - insulated / plastic / with knockouts
SK-29 Knockout Electrical Enclosures | SK Series NEMA Box
Cantex EZ20SNW PVC 1-Gang Residential New Work Electrical Switch and Outlet Box with Knockouts 2-1/4-Inch x 3-7/8-Inch x 3-1/8-Inch 20.3-Cubic-Inch EZ Box - Walmart.com
Plastic Electrical Box Knockout Plugs at Lowes.com
Carlon 6 in. x 6 in. x 4 in. Gray PVC Junction Box E987RR - The Home Depot
Safe to use caulk to air seal around wires coming into the outlet box through knockout holes? - GreenBuildingAdvisor
Carlon 1-Gang 14 cu. in. PVC Old Work Electrical Switch and Outlet Box B114RB - The Home Depot
DJC Supply Co. 6" x 6" x 3" PVC Plastic Junction Conduit Box with 3/4" & 1" Pre molded Holes - Amazon.com
Plastic Electrical Box Uses
A238-CARLON - Carlon A238-CARLON - 2-Gang ENT Non-Metallic Outlet Box w/ Eccentric Knockouts, 4" Square, 38 Cubic Inch
How to make a hole knockout in a electrical back box enclosure - YouTube