SIMPLE. RUGGED. MINIMALIST The ST System combines Hollis' most popular single tank components into one, both including the Solo harness for the ultimate in simplicity and streamlining. This kit is preassembled from the factory and includes unique components depending on the configuration. For warm water and travel destinations there is the ST Travel, which includes the ST22 wing Aluminum backplate 2.0, Delrin cam bands and Backplate backpad 2.0. While those diving in colder waters can choose the ST System, which includes the ST35 wing, Stainless Steel Backplate 2.0 and Backplate backpad 2.0. ST35 Wing 35lbs lift) Solo Harness w/ Stainless Steel Backplate 2.0 Backplate Backpad 2.0 Stainless Steel Cam Bands