Amazon.com: BL1830 BL1840 Replacement 18V 3000mAh Battery for Makita 18V LXT Lithium-Ion BL1815 BL1830 BL1835 BL1840 BL1845 BL1850 BL1860 LXT400 Cordless Power Tools Battery : Tools & Home Improvement
Amazon.com: MechanicAnts MA21007 Lithium-Ion 20V MAX 4.0Ah Battery for All MechanicAnts Power Tools, Compatible with Makita BL1840 : Tools & Home Improvement
2Pack BL1840B 4.0Ah 18V Replacement Battery for Makita 18v Battery Lithium Compatible with Makita 18 Volt Battery BL1815 BL1820 BL1830 BL1840 BL1850 - - Amazon.com