From Plugged In Golf:
"Starting with a wide lens, the TENSEI 1K Black is a stout, tip stiff shaft. In this, it’s similar to the 1K White. Where they differ is that the 1K Black feels stiffer throughout. With the 1K White, there’s a noticeable amount of flex in the butt section. The 1K Black doesn’t have that. This is a shaft you can really lean on and swing aggressively. It stops short of being boardy or harsh, but you never have to worry about this shaft getting loose." Click here
to read the full review.