The first generation tools had a 1.3 amp hour battery. These replacement batteries hold a charge much longer. Also Ni-cad batteries have a somewhat short life span so if your batteries are more then a year or two old they will not take a complete charge.
Please note this is a Ni-Cad battery for the older style EK425 crimpers and will not work with the newer Lithium battery powered tools.Cat# RAM3GLUPC# 89818Mat# 52026639