FYI this is U3 V30 card which means it guarantees a minimum write speed of 30 MB/s which is what you want for 4K direct writing. Its normal write speed can exceed that but it has this guaranteed minimum rating which is what you want from an SD card these days.
It also has an A1 rating which is a rating for Random Read performance. Its not as good as A2 ratings, but obviously better than cards that don’t have the A1 rating (older standard cards).
If you are looking for an SD card for dashcams and constant writing, I recommend that you buy high endurance cards and not these. They will give much more millage compared to the money you spend and are better for those applications.
Also pay attention to shipping price, as it may differ whether you order 1 or more. Also make sure you check which seller you are buying from. This post is regarding the sale from Silicon Power USA as the seller.
I was on the lookout for a good price for many months, and finally this dropped. I purchased 2.
Amazon product: Silicon Power U3 128GB Micro SD Card Nintendo-Switch Compatible, SDXC microsdxc High Speed Class 10 MicroSD Memory Card with Adapter
Rated for 80MB/s write speed. I tested a large file and got consistently around 70MB/s. More than sufficient for recording 4k video. Way cheaper than the big brand names, very close performance and much lower price. Also tested for capacity, and it is true 128GB (minus the usual formatting). It would have been nice to include a small card holder for people who don’t have dedicated card storage, but that’s a minor complaint. I will definitely be buying more.