All our balsa is graded for normal modelling use. For example 0.8mm (1/32") sheet would be hard, 1.6 to 6.5mm (1/16 to 1/4") would be medium and 9.5mm (3/8") sheet and over would be soft.
If your balsa requirement is different to normal use, you can specify an alternative grade before adding it to your shopping basket.