If you want to start diving doubles with your Hollis back plate then you're going to need a set of these double mounting plates. The Hollis HTS Double Mounting Plates allow you to attach twin cylinders to twin capable Hollis back plates. Stainless steel construction and are sold in packages of 2. The Stainless Steel Mounting Plates firmly secure a set of double tanks that uses industry-standard bands and bolts. They are curved to fit the spacing of double tanks. 

Features: 

• Attach 2-Tanks to Hollis Back-Plates
• Completes Secure Dual Tank Setup w/ Industry Standard Cylinder Bands
• Stainless Steel Construction
• Package of 2