Artisan Power EnGenius DuraFon, Durawalkie, SP-922 PRO Phones: Replacement Battery. 2000 mAh EnGenius DuraFon 1x, DuraFon 4x, Durawalkie, DuraFon Pro, SP-922 PRO and SN-902 Replacement Battery Fully replaces OEM battery DuraFon-BA Lithium Ion Rechargeable Battery Pack | 3.7 Volt | Cells Made in Japan | 2000 mAh Capacity Rating Longer Lasting: 2000 mAh capacity rating 18% higher than the OEM batteries. Manufactured by Artisan Power, a leader in premium quality replacement battery packs.