Thai Stone Mortar and Pestles.
For freshest sauces and herbs, grind your own from scratch and just before using for maximum flavour, freshness, and nutrient level- not to mention colour brilliance.
Now as for stated measurements, it is often found that inches are different in China,
maybe this is general throughout the East?
Anyway, the 8 inch is more like 9 inch outside width, and the 7 inch is more like an 8 inch.