Duravane 50 CT - TAPERED BLADE; The blade on all DURAVANES(R) has a slight taper from base to top for unbelievable size/weight versus steering power. This allows use of a much smaller vane than usual for a specific size shaft. This design also eliminates blade flap and unwanted noise. SUCTION FIT BASE; Our base, fitting any shaft size, is specifically designed for an instant airtight surface-to-surface bond. Most cyanoacrylates (super glue) make this bond indestructible. NO PRIMER ON THE VANE; Because our blend of materials requires no primer or any other material on the base of the vane for adhesion, DURAVANES(R) have an unlimited shelf life. DURAVANES(R) have been designed and tested to outperform any other vane, (or feather) in all aspects.Style: VANE40D