Here's another puzzle lock from Rainer Popp's series of Popplocks. This is the Popplock T4:
As you have probably worked out this is the fourth lock in the Popplock series, and even though the solution is completely different to the others it does have some things in common. Once again this lock is machined from solid brass block and stainless steel, so this thing is heavy! The key is also really good quality, so there was no chance I'd end up breaking it like I did with the T2. I personally think that the T4 looks really nice! Not quite as nice as the T3 perhaps, but still very nice.
The first thing I noticed about it when I got it is probably the same thing you notice from looking at the pictures, and that is that you are looking at a lock that has a key but no key hole, which I found really intriguing! The T4 requires you to complete five very unique steps to complete the goal which is the opening of the shackle. My experiences from opening the T2 and T3 didn't really help when it came to this one, none of the steps were the same. The first two (depending on how you count them) steps are relatively easy to find, but the third had me well and truly stumped for a long while. As I was trying this lock out at the MPP I didn't want to leave it unsolved in case I didn't get another chance at it for a long while, so a friend had to point me in the right direction. And I can say with some certainty that it would've taken me a whole lot longer if he hadn't helped me out. I agree with what Brian says in his review, this particular step could've been made a little bit easier to find without taking away from the overall enjoyment of solving it.
Now that I have solved all of the Popplocks I can say that the T3 is still my favourite, but now the T4 comes in as a very close second place. It is definitely a great puzzle, but whether it is worth the very hefty price tag is really up to you.
I tried this lock out at the MPP, but you can buy it from Grand Illusions and Puzzle Master.
Also read: My review of the Popplock T2 and My review of the Popplock T3