Found this looking for a decent replacement 64GB USB Flash. Not the fastest, but a good compromise with price (if you are eligible for free postage). My title got edited, but free shipping for Ebay Plus users.
Up to 200MB/s transfer rate (300MB/s for larger drives)
USB 3.1 (Compatible to USB 2.0)
5 Proof (Water, Shock, Magnet, Temperature, X-Ray)