The JBO Thread Plug Gauge is a right-hand Go/No-Go gauge designed for metric fine threads, specifically M4 x 0.25 in 5H tolerance. It helps quality teams, machinists, and assemblers quickly verify threaded holes meet spec, ensuring parts fit together with confidence and minimal rework.

• Go/No-Go quick thread checks: Quickly verify the hole thread against M4 x 0.25 with 5H tolerance, delivering a clear pass/fail result to speed up inspection and reduce guesswork.
• Hardened steel for long-lasting accuracy: Built from hardened steel to resist wear, maintaining consistent measurements across many uses and demanding job sites.
• Ergonomic, dual-ended design for reliability: Knurled body with dual threaded ends provides secure grip and straightforward alignment, supporting repeatable checks in daily workflows.

Using this gauge streamlines threaded-hole inspection, shortens inspection cycles, and helps ensure reliable assembly by clearly confirming which holes are in tolerance. Its durable construction and precise Go/No-Go design give you a dependable tool that supports consistent quality across repetitive tasks and busy production lines.