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
Amazon.com: 【Upgrade Current Protection】 TenHutt 6.0Ah 18V Lithium-Ion Replacement Battery for Makita 18V LXT Battery Compatible with BL1830 BL1840 BL1850 BL1860 BL1815 BL1860B Cordless Power Tools : Tools & Home Improvement