Amazon.com: Lego Education Pneumatics Add-on Set 9641 : Toys & Games
Mechanisms Pneumatics Add-On Set : Set 9641-1 | BrickLink
LEGO 9641 Education Pneumatics Add-On Set | BrickEconomy
Moc Technical Hose Air Pump Tank Push Rod Putter Switch Piston Compatible With Legoeds Pneumatic Parts 9641 42043 47225 61904 - Programmable Toys - AliExpress
LEGO 9641 Pneumatics Add-On Set Instructions, Education
Pneumatics Add-On Set - LEGO Education 9641
LEGO 9641: Pneumatics Add-On Set | Brickset: LEGO set guide and database