Another product in the organic polymer family is KEMET's Face Down T528 series. In addition to low ESR, the T528 also offers low ESL. The Effective Series Inductance (ESL) of a capacitor is defined by the restriction of current flow within the device. The larger the cross section of the path which the current can flow, the lower the ESL and the longer the path the current must flow (or current loop), the higher the ESL. The ESL in standard chips of 1.8 to 1.5nH is reduced to 0.7 to 0.4nH (depending on case size) in the face down package. Looking at the range where the impedance is less than 10mΩ, the T520 runs from 55kHz to 724kHz and the T528 runs from 65kHz to 2.3MHz, thus simplifying high frequency decoupling.