DJC Supply Co. 4" x 4" x 3" PVC Plastic Junction Conduit Box with Pre Molded 3/4" & 1/2" Conduit Holes, Easy to knock out covers, Metal screws - Amazon.com
Carlon 4 in. x 4 in. x 2 in. Gray PVC Junction Box E989NNJ-CAR - The Home Depot
Crouse-Hinds Series TP403PF 4 x 4 x 2-1/8 Inch Steel Welded Square Outlet Box | Capital Electric Supply
1 Gang Rectangular Electrical Junction Box Galvanized Steel 2x4 Inch