Synergy Digital Wireless Headset Battery, Works with Sennheiser DW PRO 1 Wireless Headset, (Li-Pol, 3.7, 180mAh) Ultra High Capacity, Compatible with Sennheiser 504374, BATT-03 Battery - Walmart.com
Sennheiser D10 DW Office DW Office ML DW Pro 1 DW Replacement Battery: BatteryClerk.com Headphone
Replacement Sennheiser DW Pro 1 Headset Battery | Battery Mart