Amazon.com: LEGO Technic 4 pcs NEW YELLOW MINI PNEUMATIC PISTON CYLINDERS Air pressure Pump pack lot set switch hose small little robot robotics : Toys & Games
Pneumatic Cylinder with 2 Inlets and Rounded End Medium (48mm) : Part 47224c01 | BrickLink
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
LEGO part x189c01 - Yellow Pneumatic Cylinder with 2 Inlets Small (32mm) at BrickScout