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
Pro Instructions - 1 Cylinder Switchless Lego Pneumatic Engine 2500 RP – Green Gecko Workshop
Pneumatic Cylinder V2 1 x 11 : Part 21828c01 | BrickLink
LEGO 5116 Technic Pneumatic Piston Cylinder 32 mm | BrickEconomy
LEGO part 4688c01 - Yellow Pneumatic Cylinder with 1 Inlet Medium (48mm) at BrickScout