FX-BATT-E-B1 Battery back for E2 series 3.6V Replacement battery for E2 sensors, can be also used temporary to power up repeaters. Datasheet (www.fidelix.com): FI, EN, SE, NO, FR, DK, DE, CH, NLRelated product:Configuration dongle: FI, EN, SE, NO, FR, DK, DE, CH, NL