The K&F Concept microSDXC UHS-I memory card 64GB is supplied together with an SD card adapter in a blister pack that can be opened without frustration. In the item description, it is advertised as a UHS-I U3 card, which means it should have a write speed of at least 30 Mbytes/s.

The card and the adapter are well made, and the contacts also make a solid impression.
The card is recognized immediately by my devices and the available storage space is indicated correctly.

I ran the "H2testw" memory card test tool twice on the memory card: The card is 100 percent correct and shows no weaknesses when writing and reading the test data blocks. H2testw has a writing speed of 43.4 Mbytes/s and a reading speed of 79.3 Mbytes/s. The SpeedOut tool determined a write speed of almost 52 MB/s and a read speed of a good 84 MB/s with my Thinkpad E 15 Gen2. This means that this no-name card is extremely fast.

For further tests, I put the card in my GoPro: 4K videos are possible without restrictions and jerks. This card is more than fast enough for use in a surveillance camera or dashcam!

Considering the good writing performance, give this card 5 stars.