The battery unit is slightly larger than the original battery. However, with a bit of force , the battery cover did close. My concern is that the pressure on the battery unit by the cover would result in a failure of the power leads from the battery. I did notice that the original battery is a NiCad, while the new battery is a Ni Metal Hydride. But the container box identifies it as a BT-1007H, which is the same designation of the original battery.
However, after a week of use, the battery has charged, and the phone is working perfectly. I suggest that the description of the replacement battery should identify that this is identical in form, but an improvement in battery chemistry.