Lego XL Linear Actuator Kit (technic,cylinder,piston,bracket,robot,power) | eBay
LEGO TECHNIC - 2 x Mechanical control cylinder (Linear Actuator) mini with brackets: Amazon.com: Industrial & Scientific
UPDATED] Lego Technic linear actuator performance measurement (including new XL actuators) - LEGO Technic, Mindstorms, Model Team and Scale Modeling - Eurobricks Forums
LEGO® Technic Power Function linear actuator linear drive DK. ST. GRAY/BLACK (DARK STONE GRAY/