The Aastra Telecom BE-3850 Model A (Slide-In) cordless phone Battery will solve your battery problems or provide you with a spare battery. The Aastra Telecom BE-3850 Model A (Slide-In) cordless phone Battery comes with a 30 day money back guarantee and a 1 year free replacement warranty. Once we have received your new order for the Aastra Telecom BE-3850 Model A (Slide-In) cordless phone Batteries, it will be processed within 24 hours or on the next business day with Free Shipping via USPS First Class Mail.