Evans AF Patch™ is an Aramid Fiber bass drum patch that provides unsurpassed durability and emphasizes attack characteristics. Four radial slits along the perimeter allow the head to vibrate naturally for better tone and feel. For over 60 years, Evans has been an innovator in drumhead manufacturing and design. As the creator of the first synthetic drumhead and other revolutionary products such as EMAD, Hydraulics, and the UV1 series, Evans drumheads are designed with the intent of solving problems for drummers. Regarded for high quality and consistency all Evans drumheads are made in the USA and feature Level 360 Technology., Single Pedal version, add two for double pedals, 2 patches per package, Increases attack without affecting sustain or low end, All Evans accessories are designed, engineered and manufactured in the USA