Carlon 3-5/8 in. Round 1 Gang Ceiling Box - Volume 25 Cubic Inches, Diameter 4 Inches, Depth 2.95 Inches, Color Blue, Material PVC, Mounting Means Hanger Bar 11-1/2 Inches - 18-1/2 Inches. Resists flexing and holds their shape even in the worst applications. Listed for fixture support up to 50 lbs.