The Padlock is the cheapest flash drive here, but it costs £8 per gigabyte. It feels sturdy enough, but there's nowhere to put the cap when detached. It has a keypad security system, allowing you to lock access to the drive via a PIN. The drive was quick to read files, but its average write speeds place it halfway down the group overall.
The security system will appeal to some, but Corsair's 4GB Voyager is better value.