Technic, Gearbox 2 x 4 x 3 1/3 : Part 6588 | BrickLink
Amazon.com: Eske Kouri Gobricks GDS-1324 Technical, Gearbox 2 x 4 x 3 1/3 Compatible with Lego 6588 32239 All Major Brick Brands,Building Blocks,Parts and Pieces (194 Light Bluish Gray(071),5 PCS) : Toys & Games
Gobricks GDS-1324 Technical, Gearbox 2 x 4 x 3 1/3 compatible with lego 6588 32239 children's DIY Educational Building Blocks - AliExpress
LEGO Black Gearbox for Worm Gear (6588) | Brick Owl - LEGO Marketplace
Bricker - Part LEGO - 6588 Technic, Gearbox 2 x 4 x 3 1/3
LEGO 6588 Technic, Gearbox 2 x 4 x 3 1/3 - FREE P&P! | eBay
Gobricks GDS-1324 Technical, Gearbox 2 x 4 x 3 1/3 compatible with lego 6588 32239 children's DIY Educational Building Blocks - AliExpress
HELP] Things to make with Gearbox (6588) - LEGO Technic, Mindstorms, Model Team and Scale Modeling - Eurobricks Forums
Amazon.com: Eske Kouri Gobricks GDS-1324 Technical, Gearbox 2 x 4 x 3 1/3 Compatible with Lego 6588 32239 All Major Brick Brands,Building Blocks,Parts and Pieces (194 Light Bluish Gray(071),5 PCS) : Toys & Games
Amazon.com: LEGO Technic COMPLETE GEARBOX ASSEMBLY 2 x 4 x 3 1/3 Trans-Clear Wormbox gear motor REDUCER block Mindstorms robotics ev3 NXT transparent robot building power functions part 6588