It's designed for single tank use.
The air cell is extremely streamlined and its frontal width (as the diver assumes swimming position) is barely wider than an average person's shoulders.

• Low pressure BC hose included.
• Style: Circular doughnut
• Bouyancy capacity: 40lbf (18.1kgf)
• Bladder material: 420D TPU coated nylon
• Shell material: 1680D TPU coated nylon
• Inflator length: 16'' (40.6cm)(tech elbow)
• No. of automatic pressure relieve valve / pull dump: 1 (at left waist side)
• Mounting grommets distance (C-C): 3 sets in total, 11”(27.9cm)
• For single back mount tank only (100cuft / 15L internal volume)