· Outer Dimension: 28" x 17-1/4", Dome Dimension: 24" x 14-1/4" x 7"· Made of durable, impact resistant polycarbonate· Industry leading quality skylight - Thicker and stronger than the original OEM skylight· Take the dimensions of your skylight opening on your RV and compare them with this skylight to ensure a proper fit for your unit· Use ICON Skylight Sealant for install