We may earn a commission from links on this page. Deal pricing and availability subject to change after time of publication.One of my biggest pet peeves about the Oura ring platform is getting some temporary relief, thanks to Amazons spring sale. Chargers for the gen 4 ring (the newest model) are available for $35.40 today, so you can pick up a spare for close to half the usual price. Oura Ring 4 Charger $35.40 at Amazon $59.00 Save $23.60 Get Deal Get Deal $35.40 at Amazon $59.00 Save $23.60 And, yep, the usual price for an Oura charger is a whopping 59 bucks. The old gen 3 chargers dont fit the new gen 4 rings, and the chargers are also sized: If you have a size 8 ring, you need a size 8 charger. And there arent third-party chargers for the gen 4 rings, so the official Oura ones are your only option. Hence my griping about the price.But now, at $35.40? Thats still not cheap, but its a lot better than full price. Your ring will have come with one charger, but its handy to have a spare so you can keep one at your work desk and one on your nightstand, or to keep an extra in your travel drawer.The Oura ring lasts most of a week on each chargeup to eight days, according to the company, although I found I only got about five days between charges with blood oxygen sensing turned on. That also accounts for charging the ring when it falls to 20% battery, which is the app's recommendation to be sure it won't run out of juice while you sleep. The fourth generation Oura ring has a good reason for not fitting the old chargers, by the waythe old rings had three sensor bumps on the inside, where the gen 4 has finally managed to fit its technology into a smooth interior that fits like a normal ring. So the ring is a different shape on the interior, and the sizing has also changed. For more on the differences between the gen 3 and gen 4 Oura rings, I have a detailed comparison here. Ive also worn three different generations of the ring over the past four years, and I wrote a retrospective here with all my thoughts on how Ive used my ring over the years, and where it has and hasnt lived up to my expectations.Shopping for tech? Lifehacker can help you make the right decision. Browse our tech reviews and head-to-head comparisons for everything from laptops and smartwatches to e-bikes and home gyms. Subscribe to our deals newsletter, Add to Cart, for the best sales sent to your inbox, or browse our best-of lists directly on Amazon, including:The Best Over-Ear HeadphonesThe Best Wireless EarbudsThe Best Adjustable Dumbbell SetsThe Best Projectors