Lego Technic Axle 6 Mindstorms 3706 Black x6 | eBay
LEGO® Technic Cross Axle 6M / 6L with Groove BLACK (BLACK) - (370626/3706)
LEGO 3706 Fabuland Ernie Elephant | BrickEconomy
Amazon.com: LEGO TECHNIC 100 pcs BLACK AXLE SIZE 6 STUDS STUD LENGTH Cross Rod Mindstorms robot motor short medium part piece 3706 NXT ev3 robotics : Toys & Games