Made specfically for the Summit Van Co roof racks but universal to any rack that utilizes 1.5" aluminum tubing.  Our custom roof rack crossbars are made from aluminum with custom aluminum CNC tube clamps and stainless hardware.  The crossbars are fully adjustable to work with nearly any width of Sprinter roof rack with 1.5" OD top rails.  The clamps are machined to allow for powdercoating and come powdercoated in the highest quality powder coating on the market.  The crossbars have drainage holes and a set bolt to ensure no rattling or movement of telescoping inner bar.
 
Each bar (sold separately) is rated at 300 lbs.  These bars are heavy duty.  The price is justified when you see the quality.