The Hollis Back Plate is engineered to Fit-Closer to the Cylinders, creating a Tighter-Profile and as a result Reduces Drag. The Edges on the Outside of the Hollis 5052-Grade Hard Black Anodized Aluminum Back Plate are Radius-Formed to fit the Hollis BC, thereby preventing Back-Plate-Chafing of the BC. The Webbing that passes through the Slots in the Back Plate must continue to function throughout the dive season without appreciable abrasion. The Slots, Holes and Edges of the Hollis Back Plate are Fully De-Burred Eliminating Sharp-Edges that can cut you and your harness system. The Hollis Aluminum Back Plate weighs 32oz (907.2g), making it the Travelers Choice and is covered by a 24 month limited warranty.