Pro Ultrasonic Discs The latest disc design and the worlds first brass disc with holes. Pro Sportfisher Ultra Sonic Disc combines weight and added mobility for the fly, while the vented design allows for an easier lift-off for a new cast. The Pro Ultra Sonic Disc shape is optimized to add the desired effect, but still very easy to lift of the water due to the venting holes, while maintain the capability to create a vortex behind the disc, allowing soft modern materials to swim freely instead of collapsing in hard current. Available in: S: 7,0 mm M: 9,0 mm and L: 11,0 mm