If you close your hand (just as you would when gripping a screwdriver), you will notice that a rounded triangle is the best fit. These screwdrivers have such handles.
Not only do they feel good in your hand, but they also allow you to apply great torque without using a death grip. The handles have fitted steel end caps and the through tang is fitted to a chromed striking cap. The blades are well hardened and magnetized.
Made in Japan.