Terminology, reference = 3 (= 3 x 1/8 = 3/8") B = British Standard,
-1 = Simplex (one row of teeth)
Last 2 numbers denote number of teeth
e.g. 31.38 = 3/8 pitch, Simplex, 38 Tooth Sprocket
To suit British Standard Roller chain :-
06B-1 (B.S. Reference), 110038 (Renold), 3SR (Morse)
