6ply, 5.6mm 100% Maple Shell All-maple shells give Tour Custom drums their warm, bright tone. These shells are designed with a 6 ply-5.6 mm / 45 degree bearing edge that adds tonal depth and quick response and provides just the right amount of sustain. 2.3mm Inverse Dyna Hoop Newly-designed 2.3 mm Inverse Dyna Hoop controls the natural overtones inherent to all-maple drums and focuses the fundamental tone of the shell. Absolute lug Shells feature exclusive Yamaha absolute lugs. Their sophisticated design adds a touch of class to the drums. P Type Strainer Improved P Type Strainer is designed for ease of grip and smooth operation. Butt side also offers adjustable height. Strainer lever utilizes a silicon rubber for secure locking with quiet operation.