Image Item No. Description  4019  Technic, Gear 16 Tooth - Axle Hole with Open Sides Catalog: Parts: Technic, Gear  6542  Technic, Gear 16 Tooth with Clutch Catalog: Parts: Technic, Gear  6573  Technic, Gear Differential 24-16 Tooth Catalog: Parts: Technic, Gear  6592  Technic, Gear Rack 1 x 10 with Holes Catalog: Parts: Technic, Gear  6588  Technic, Gearbox 2 x 4 x 3 1/3 Catalog: Parts: Technic, Gear