V-12 reeds are manufactured from cane tubes of the same diameter as those used for saxophone reeds. This leads to a higher manufacturing cost, as large diameter cane is rarer.
V-12 reeds are thicker at each end:
Thickness at the tip: .10 mm (0.004 inch)
Thickness at the heel: 3.15 mm (0.124 inches, hence the name V-12)
In comparing strengths, a V-12 strength 4 reed is almost equal to a Traditional strength 3 1/2 reed.