The KAI 7230 - 9" Professional Shear is ideal for thicker, more difficult fabrics. The 7000 Professional Series, including the 7230, are made of a high carbon, hardened stainless steel. The addition of carbon allows for a steeper cutting angle, giving the scissor a sharper, finer edge. The carbon allows the finer edge to last longer. This gives the 7000 series a better ability to cut thicker fabrics and allow for easier use.
The KAI 7230, being a 9", is considered a lighter shear, yet long enough for standard sewing projects. Most people compare this shear to the KAI 7250 10" shear. When compared, the KAI 7230 is better suited to people with smaller hands or desire lighter weight.
*NOTE: The difference between the KAI 7230 9" and KAI 7250 10" is that you gain the extra inch in the handle, not the blade.