Extend your capacity - the TimberLine attaches to factory racks with raised side rails to expand your carrying capacity and deliver maximum rooftop versatility. Secure and super-sleek, they are quiet, simple to install and work with all of our bars. Product Details Complete set of 4 TimberLine Towers Advanced tower architecture is sleek, strong and quiet Sleek tower cover styling with matte black finish to match modern vehicle styling Works with JetStream, CoreBar and RoundBar crossbars Strong, durable stainless steel strap to accommodates a range of rails Maximum load rating of 220lbs (100kg), depending on vehicle and bar rating Easily locks to you vehicle with our SKS system (sold separately) RoundBar SL Adapter required to use Yakima&';s classic RoundBar with StreamLine System Towers (sold separately) HD Bar SL Adapter required to use Yakima&';s HD Bar with StreamLine System Towers (sold separately) Product Specs Weight: 5.00 lbs. Dimensions: L 6.00 in x W 3.50 in x H 3.00 in