The 3 Inch Tube Framing Clamp design allows the Main Tube support to be installed right at the top of the roof deck flutes. Each End Clamp is rated for 250 lbs or a complete system load rating of up to 1,000 lbs in uplift or download conditions. The 3 Inch Tube Framing Clamp System is the support of choice for all skylight, exhaust fan, roof hatch and other light duty roof penetrations.