Amazon.com: Goshfun 32Pcs 10-Kinds MOC Pneumatic Parts Bricks with Air Pump Push Rod Switch Piston Air Pipe, DIY Small Particle Stem Building Blocks Toy Set Compatible with Lego, Random Color of Air
Pneumatic Cylinder with 2 Inlets Small (32mm) : Part x189c01 | BrickLink
Exploring Piston Engine Design With LEGO | Hackaday