Grade AA, A and B are manufactured and inspected under the JIS B 7510 standard. Grade AA has ±0.2 scale all range accuracy in the main bubble Grade AA and Grade A have an insulating material which prevents heat transfering. Grade AA and Grade A have a bubble chamber in which the length of the
The Precision Flat Level is a high-precision measurement tool manufactured and inspected under the JIS B 7510 standard (applicable to Grades AA, A, and B). Designed for accurate leveling applications, this instrument is available in multiple size variants ranging from 100 mm to 600 mm, with options for sensitivity ratings including $0.02\text{ mm/m } (4')$, $0.05\text{ mm/m } (10')$, and $0.1\text{ mm/m } (20')$.