Both batteries are very thin (the Stripe is just o.3mm in depth) meaning that they add no visible bulk while increasing battery life. This is similar to smartphone cases that include a battery.
The Band variant is designed for smartwatches while the Stripe is designed for other accessories, such as necklaces and headbands. According to Samsung, the Stripe add-on can withstand up to 50,000 “bends.”
Recently, Samsung announced that it had been working on a new smartphone battery that could extend usage by up to 21 hours. The company achieved this by making the batteries denser, adding extra capacity for charge.
Both the Band and Stripe are prototypes at this stage and Samsung declined to give a release date.