Evans Tri-Center Conga Drum Head, 11.00 Inch 11" drum head with two plies of 10mil film with a 2.25" patch between Bright, penetrating slap tone with a full, round low-end Etched texture simulates the feel of animal skin while avoiding the problems associated with natural skin heads Tri-Center minimizes overtones and adds weight to the center to enhance the fundamental tone All Evans drum heads are designed, engineered and manufactured in the USA