You've likely seen 128GB micro SD cards for cheaper than this. However, those sport slower read and write speeds, as this model here from Samsung boasts 80mb/s which means it'll be great for recording 4K video and give you an all around better experience. Especially if you are using a micro SD card in your smartphone. This micro SD card will work in smartphones like the LG G5, HTC 10, Samsung Galaxy S7, and plenty of others - although the Nexus 5X and Nexus 6P do not have a micro SD card slot, unfortunately.
This model here is waterproof, so even if it gets dropped in a pool, bathtub, sink or toilet, your data won't be damaged. Additionally, it is X-ray proof, so it won't get damaged when it goes through security at the airport. While this micro SD card does sport 128GB of storage, you won't have that much available to you. It'll be closer to around 118 to 120GB of storage. That's still a pretty decent amount to be able to add to your smartphone, however. It's on sale right now through Amazon for just $45.99, and there's no telling how long it'll be available at that price, so you'll want to grab it before it's gone.