Vtech DS4121 Cordless Phone Battery Combo-Pack Includes: 4 x SDCP-H303 Batteries (4) Pack Replacement Batteries for Rechargeable - Ni-MH 1X3AAA/D, 3.6 Volt, 800 mAh. These Batteries are fully Compatible with the original battery You can rest assured that these batteries will work with your Cordless Phone, And it will charge in your Phone. We use only high quality Japanese cells, so you are sure these batteries will last for years to come. Synergy Digital is a very high reputable company that manufactures and distributes batteries and other electronic accessories for over 2 decades, this product comes with a 1 year manufacturer warranty.