Ultra High Supercapacitors Eaton Ultra High Supercapacitors feature low Equivalent Series Resistance (ESR) with high energy density and ultra-high capacitance devices utilizing Electric Double-Layer Capacitor (EDLC) construction. This construction is combined with high-performance materials. These supercapacitors are RoHS compliant. The ultra-high supercapacitors are ideal for bridging or hold-up power.