Series match the type of wood used and the shell thickness to create a more natural sound for the diameter of the drum. This creates a naturally higher and sharper tone with slightly less decay. This creates a nautrally lower fundamental note and longer sustain. The 20 bass drum shell is the same 6ply with 4.8mm shellcoupled with 6ply Maple SoundRing to fatten teh bearing edge and create a low Punch. With close to 40 years of drum manufacturing experience we understand how different woods present different tonal characteristics. With this in mind there is not one wood type that is best at serving the purpose of every drum within the drum set. ParaSonic combines hand-selected sheets of two of the most popular woods used for manufacturing high-end drums: maple and birch. We use the natural characteristics of each wood to create a tailored sound for each drum and its purpose within the set. That being said maple has a naturally warm well-rounded tone with a balanced mix of bottom end punch lower mid-range warmth and hi-end attack. Birch on the other hand has naturally brighter tone with accentuated highs resulting in increased attack and presence. ParaSonic s rack toms utilize a blend of maple and birch with a thicker shell to produce brighter tone increased attack and shorter sustain. Floor toms utilized with a thinner shell resulting in deeper tone and increased sustain.Features North American Sugar Maple and Premium Birch hybrid Shells 8 to 12 are 2ply Maple & 4ply Birch 6.2mm Shells 14 to 22 are 6ply Maple 4.8mm EFS Shell Technology 6ply maple Sound Rings on bass drums ParaSonic Lug UB105 Pocket Hinge Bracket BC100 Articulated Claw Hook Brilliant High Gloss Lacquer Finishes Studded Gaskets Slide Track Tom Holder System Suspension Rings for Rack Toms 2.3mm Counterhoops 4 PieceSpecifications Color: Walnut Burst Size: 20 in. Dimensions 1: 24 H x 19 W x 24 L Dimensions 2: 15 H x 21 W x 15 L Weight 1: 43 lbs Weight 2: 22 lbs - SKU: TYDM001