Home Depot offers the Ryobi 18-Volt One Plus Lithium Plus Battery 2-Pack, model no. P109, for $99. Pad your order over $100 (this lock nut costs $1.18) and apply coupon code "SPRINGHD" to cut it to $89, excluding the cost of padding. With free shipping, that's tied with our mention of a similar, but larger, 2-pack from earlier today (still available) and $11 under what Home Depot charges for these batteries individually. (It's also $101 under the best price we could find for this quantity of batteries combined with chargers elsewhere.) These batteries purport to provide up to 35% more runtime, four times longer lasting charge, and 45% lighter weight than regular Ni-Cd batteries.