As a Retired Electrical Engineer, I had replaced the batteries in my Cordless Telephone once before. The original and first-replacement batteries lasted about six years apiece. These lasted two days. The word on the street is that cheap Chinese batteries don't last after being discharged -- they become "Bricks" (useless). So I bought a new Cordless Set with AA-size rechargable batteries -- to widen the sources of supply.Lenmar CB0105 Battery for Panasonic Cordless Phones