JBO Thread Ring Gauge (NoGo) - Metric Fine - Left Hand - 6g - M52 x 1 Hydraulic Expansion Chucks it helps inspectors confirm that

it helps inspectors confirm that parts meet the required thread form and diameter

and the stock note refers to blanks ready to be machined into the reamer you need

Runout: 13–15 micron runout

Taper Shank design for secure mounting: Fits standard toolholders and machines

User‑Friendly Left‑Hand Orientation: Designed for left-handed threaded components

JBO Thread Ring Gauge (NoGo) - Metric Fine - Left Hand - 6g - M52 x 1 Hydraulic Expansion Chucks it helps inspectors confirm thatThe JBO Thread Ring Gauge (NoGo) Metric Fine, Left Hand, 6g, M52 x 1 is a precision inspection tool designed to quickly verify external threads on components. Built for machinists, quality engineers, inspectors, and maintenance teams, it helps you confirm that a parts outer thread matches exact size and tolerance before assembly or machining. With a dedicated left hand design for left handed threads, this NoGo ring makes pass fail decisions fast and