These JMP replacement blades are available individually and fit all 3 units: the original JMP, the JMP-v2, and the JM-SW.
The Crosscut A blade is the most commonly used blade for the Jointmaker series saws.  It is 28 tpi and leaves a kerf of 0.021" (0.53 mm).  It works well for both crosscuts and also for rip cuts like dovetails in a variety of woods.