These USB cables are suitable for a maximum current of 2.5A. Please keep dry and do not touch water, use the appropriate charger which is suitable for your smart phone current and voltage. Standard USB 2.0 transfer speeds up to 480Mbps. Support quick charge 3.0 or 2.0. And it may not fit your waterproof cellphone case. You can hang them on bags, keys, cell phone cases... It's so cool !