Comparison : Item # 12B11, No. 12B - 3/4" Pitch - British Standard Sprockets
Item # 12B12, No. 12B - 3/4" Pitch - British Standard Sprockets
Item # 12B13, No. 12B - 3/4" Pitch - British Standard Sprockets
Item # 12B14, No. 12B - 3/4" Pitch - British Standard Sprockets
Item # 12B15, No. 12B - 3/4" Pitch - British Standard Sprockets