Contraptions in Wolfenstein II: The New Colossus allow you to interact with the world in different ways. You can pick one at a certain point in the game, but the other two can be found in the game world. They are very useful things to have, allowing you to reach places you would not be able to otherwise, and take new routes around levels.
There are three different types of contraptions.
This allows you to reach high platforms by extending mechanical legs. If you upgrade them, they will allow you to keep overcharged health until you take damage. This is extremely useful on higher difficulties.
The Constrictor Harness will pretty much squash you, allowing you to squeeze into places you wouldn’t be able to normally. Upgrading this will increase the duration that you can stay constricted.
The Ram Shackles allow you to smash through doors, walls, and boxes. Upgrading them will allow your armor to regenerate.
The Battle Walker can be found on Venus in the Transporthalle District. While moving through this area, you will come to a large room with a single large tank in it.
Behind the tank, under the booth, is a small hole in the wall you can crouch into.
Fall all the way to the bottom and the Battle Walker contraption will be there. It’s not in this image because I already picked it up during my first playthrough.
The Constrictor Harness can be found in Manhattan Nuclear Bunkers. Around half way through this level, you will come to two large, paneled industrial doors. As you stand between them, you will be able to see a small door way ahead of you that says “Achtung Ausgang” over it. Only one of the large industrial doors will be sliding open and closed.
Go through this door, then straight ahead under a walkway, then take the next right. Run the whole way down this corridor until you are right under a Nazi flag. Climb up here (if you have no way to climb just use nearby stairs and double back) and once again take a right.
Right beside where the flag hangs down, you will see a large pile of boxes and crates. The Constrictor Harness is right there for the taking.
The Ram Shackles can be found in New Orleans, in the Bienville Street District. When you first come to a ladder that drops down to the sewers, jump down.
You can only travel one route at the moment, so keep heading forward. You will come to an intersection with some blue buckets at it. Take a left here.
Follow that route all the way, the Ram Shackles will be waiting for you at the end of it.
Hopefully this guide helps you find all the contraption locations in Wolfenstein II: The New Colossus and you put them to good use in your fight against the Nazi hordes.