LaCie has introduced a USB-C SSD: it is available with up to 2 TB capacity.
Smaller versions are available in 1 TB and 500 GB. The external SSD in a stylish case finds its connection via USB-C to the Mac. The speeds reach maximally 540 MB/s. This is below the theoretical maximum for this type of connection, but it is still sufficient for the processing of compressed 4K video.
Also included in the purchase is a limited 3-year warranty, which even covers data recovery. The small print can be found here.
LaCie has also thought about backwards compatibility and also includes a USB-C to USB-A cable: so the SSD can also be operated on conventional USB 3.0 ports. In this case you should have no loss of speed.
The external SSD will be available soon, the 2 TB is probably a bit more than 500 Euro.
Buy at Amazon: LaCie SSD