Possible face values:
2nd Class up to 100g
1st Class up to 100 g (initial value: 64 p)
1st Large up to 100 g (initial value: 96 p)
Euro 20 g / World 10 g (initial value: 1.05 £)
Worldwide up to 20 g (initial value: 1.33 £)
Europe up to 100 g (initial value: 1.52 £)
Worldwide up to 100 g (initial value: 2.25 £)
