Siemens Gigaset SL550, Cordless phone battery replacement Designed to fit (among others) cordless phones made by Siemens As a direct replacement to fit Gigaset SL550, CS-SMC55SL KP051 and the cordless phone products including Gigaset SL550, This battery is designed as a replacement in the Siemens product range, it should prove a more than acceptable replacement for the original and has a capacity of 750 , this may be higher than the original but will mean it lasts longer between charges, it is supplied by a ISO 9001 certified manufacturer and will serve well as a power source for your phone or other device as many batteries of this sort are now used for other functions. Battery Type: Li-ion Voltage of battery: 3.7V Battery Capacity: 750