A medium sound recommended for: General Signalling & Police
Bigger than 60.5, smaller than 58.5
Why it was introduced is a little vague - lost in time
Like the 63, is used by European Police forces.

{Technical}
Blowrate: Modest
Blowsound: Medium Loudness
Blowtone: Midtone
{Size & Weight}
Dimensions: 5.5(L) x 1.9(W) x 2.5(H) cms
Weight 0.03 kgs