Hydraulics feature two plies, a 7 mil outer and a 6.5 mil inner, that sandwich a thin layer of oil and give the fat, wet sound that was pioneered in the 70's. The oil decreases sustain and enhances attack and low-end. Instrument: Drum Set-Tom/Snare Finish: Black Attack: Defined Tone: Very Warm Sustain: Very Focused Feel: Firm Durability: High Available in: 8", 10", 12", 13", 14", 16