Silicone Soft and Durable Our BOOST CHARGE Flex silicone cables bring flexibility, softness, and durability to your charge. Designed with user experience in mind, our USB-A cable with Lightning connector won’t kink, resists tangling, and doesn’t get frayed. That’s because they are engineered with silicone technology, giving you a soft-to-touch and flexible experience—all while still being up to 25X more durable than ordinary cables.