https://fastenersinc.net/product/milwaukee-48-11-2442-m12-redlithium-xc4-0-battery-two-pack 2-Pack Milwaukee M12 12-Volt REDLITHIUM XC Extended Capacity 4.0 Ah Batteries (48-11-2442) for $69 (price in cart). Shipping is free on $150+ orders, otherwise it's $8.74.