From "The Evolution of Arms Law (1980-2003)" by Brent Knorr:
Claw Law was released in 1982. It adds additional tables and rules for the Rolemaster combat system. There are three versions of this, the first with loose charts and a similar one that is saddle-stitched with perforated pages. Both of these are printed on heavy card stock, with the cover and critical tables in the yellow/gold color pictured here, and the attack tables in a lighter tan color pictured below. There are also three blue pages with rules and additional tables.
The third version is a saddle-stitched book that has a blue cover with yellow/gold attack tables and blue rules and critical tables.
Claw Law provided five new critical tables: Grapple, Martial Arts Strikes, Martial Arts Sweeps and Throws, Tiny Animal, and Unbalancing. It also includes twelve new attack tables for claws, bite, stingers, trampling, martial arts etc.
One point of interest is the difference in the layout of the Attack tables in Claw Law compared to Arms Law. In Arms Law, the lowest attack number is at the bottom of the page and the highest attack number is at the top. In Claw Law, the Attack Tables are printed in landscape orientation, and the low number is at the top of the page with the high number at the bottom. Claw Law tables also include maximum results for different size attacks. A house cat is limited to the Maximum for Small Attacks on the Bite table, where a Dragon could go all the way up to the Maximum for a Huge Attack.
There are charts with summaries of Historical and Fantasy Weapons, Animal and Monster Combat Capabilities, a section with Guidelines for using Martial Arts and a table with a summary of Martial Arts Combat Capabilities, broken down by Form (Karate, Kung Fu, etc) and belt/degree.
A boxed set was also released that contained Arms Law and Claw Law.