Here's a very cool little (and I mean little) puzzle lock that had me going in circles for weeks. And also I'm not ashamed to admit that it managed to best me with it's rather simple, clever and pretty devious solution.
Rainer Popp, and it is called the Popplock T6. The version shown in the picture on the left is made with aluminium rivets, but it is also available with copper rivets for the same price. It's a matter of taste I guess, but I prefer the look of the lock fully in aluminium. The back of the main body is engraved with Rainer's signature Popplock logo and the name of the lock.
Also the key I believe is coated brass, so there shouldn't be any key snapping incidents with this one.
The main noticeable difference between the T6 and it's predecessors is that the T6 was designed to be far more affordable. As such the lock itself stands a mere 6cm tall, which is practically the same length as the key that opens it! The main body and shackle of the lock is also made from layered sheets of aluminium, so it is far easier -and I imagine- cheaper to produce than the earlier Popplocks as they were all milled from solid brass block. It also has what Rainer describes to be "only one trick", but I would say that there are two distinct steps involved in order to find the solution.
The solution as a whole is remarkably simple and yet brilliant, and even though I had a good couple of weeks with it I could not suss it out.
The key would go into the lock, and I could turn it freely. After a little while I had noticed a couple of things that were definitely useful and there for a reason, but I could not work out what that reason was! As usual I started to over-think the solution and I came up with incredibly complex ideas in my head that all turned out to be wrong.
When the time came for me to return it and I was shown the solution I absolutely kicked myself. I really should've been able to work it out. So yes; this may only be 6cm tall, be a fifth of the price of the others and only have one trick, but I promise you that this is still a Popplock!
Both the Aluminium Version and the Copper Version are still available from Puzzle Master for a very reasonable price.