QTRMSTR: QBS1 McFly is qtrmstr's first attempt in the balisong (butterfly knife) market and we'd say they execute it beyond amazingly. They have pioneered something new yet again. This time with the patented "BladExchange" system. This system allows for different blades to be purchased "a la carte" & swapped out with ease. If any of the finishes are not showing up as an option to add to cart, that just means we are currently sold out and awaiting our next batch from Qtrmstr.