A - Means tight match ( < Approx>B - Means loose match ( > Approx. 0.05mm than standard)
Gear Diameter : (Teeth +2) x modulus = Diameter of gear
Modulus: 0.5
Aperture 1.5/2/2.5/3

Spindle gear (9 styles): 8-1.5A 9-2A 8-2A 10-2A 12-2A 14-2A 16-2A 18-2.5A 18-3A
Crown tooth (10 styles): C20-2.5A C20-2A C20-3A C2410-2A C2410-2B C2810-2B C28-2A C3010-2B C30-3A C3610-2B
Single gear (18 styles): 20-2A 26-2A 24-2.5A 28-2A 30-2A 36-2A 38-2A 38-3A 40-2A 42-2A 44-2A 44-2.5A 46-2.5A 48-2A 50-3A 52-2.5A 56-2A 56-3A
Double gear (18 styles): 1810-2A 4812-2.5A 2210-2B 2410-2B 2610-2B 2808-2B 4610-2B 2810-2B 3010-2B 3210-2B 3212-2B 3412-2B 3610-2B 3808-2B 4410-2B 4810-2B 5010-2B 5610-2A
Worm gear (2 styles): 6pcs x 6-2A 6pcs x 8-2A
Pulley gear (1 styles): 6pcs x 6-2A