This standard specifies gauges for hexagon sockets with tolerances specified in JIS B 1021. Note: The corresponding international standards for this standard are shown below. The symbols representing the degree of correspondence are IDT (matched), MOD (modified), and NEQ (not equivalent) based on ISO/IEC Guide 21.
JIS B 1016:2006 Referenced Document
JIS B 1021 Tolerances for fasteners -- Part 1: Bolts, screws, studs and nuts -- Product grades A, B and C