LEGO® Technic Cross Axle 4M / 4L with Groove BLACK (BLACK) - (370526/3705)
Amazon.com: LEGO TECHNIC 100 pcs BLACK AXLE SIZE 4 STUDS STUD LENGTH Cross Rod Short Mindstorms robot motor part piece 3705 NXT ev3 robotics : Toys & Games
Lego Parts: Technic, Axle #4 (PACK of 4 - Black) by "Parts/Elements - Technic, Axles" : Amazon.co.uk: Toys & Games
Lego Black Axle 4 (10x) 370526 Brick 3705 for sale online | eBay
What does the 4 in the circle mean? : r/lego
LEGO PART 3705 Technic Axle 4 | Rebrickable - Build with LEGO