The Kastaplast Stal is an overstable fairway driver and is named for its toughness. Stal, the Swedish name for steel, was once a common soldier's name.
K1 Line is Kastaplast'ssuper durable material with a nice combination of firmness and gumminess. Discs in K1 Line will appear in both solid and translucent colors. K1 Soft is similar to K1, but flexier and grippier. Just as with K1, this plastic comes in both translucent and solid colors.