There are two other types of capacitors that also use conductive polymer electrolyte: winding type aluminum electrolytic capacitors and polymer tantalum capacitors. Winding type use a wound aluminum structure similar to conventional aluminum capacitors instead of the "SP-Cap" planar structure. The disadvantage with this type of capacitor is a tall profile, high inductance and high frequency limitations. Polymer tantalums use tantalum sintered pellets, in which the tantalum has lower conductivity than the aluminum used in the "SP-Cap". This allows the "SP-Cap" to have lower ESRs than polymer tantalums.