Amazon.com: 2 Packs Replace for Makita 18V Battery 6.0Ah, Replacement Makita 18 Volt BL1860B Batteries BL1820B 1830B 1840B 1850B, Compatible with Makita 18v Tools, Fit with Original Makita 18v Battery Charger :
Amazon.co.jp: Makita BL1840 Compatible Battery, 18 V, 4,000 mAh, Large Capacity, Lithium Ion Battery, Compatible with BL1830, BL1840, BL1850, BL1860, Set of 2 : Electronics