The plantronics replacement battery for the savi 740440 headset is a great choice for uninterrupted desk phone communication users can effortlessly charge the spare battery using a usb deluxe charger or a deluxe charging cradle this headset accessory is specially engineered to last for a longer time between charges when used with compatible devices headset battery fits plantronics savi 440 and 740 models perfectly compact form factor and lightweight design for added convenience