Bolt & Nut Size Finder Keychain Gauge – Metric & Imperial

Never Guess a Bolt Size Again

The Portable Bolt & Nut Size Finder Keychain Gauge is the compact, always-ready tool every mechanic, tradesperson, and DIY enthusiast needs. Clip it to your keys or belt loop and instantly identify bolt and nut sizes on the spot — no more guessing, no more wasted trips to the hardware store.

Made in Mainland China.

Key Features

• Fast & Accurate Size Verification: Quickly match bolt and nut sizes with clear engraved markings — reducing errors and saving valuable time on every job.
• Dual Unit Markings (Metric & Imperial): Covers both measurement systems with a measurement range of 0–80 mm, making it versatile for a wide range of fasteners and applications.
• Keychain-Ready Portable Design: Lightweight and compact enough to attach to your keyring or belt loop so it's always within arm's reach whenever you need it.
• Rugged, Durable Build: Constructed from high-quality stainless steel to withstand frequent use in demanding workshop, automotive, and industrial environments.
• Wide Application Range: Ideal for automotive repairs, home improvement projects, mechanical work, woodworking, and general industrial use.

Specifications

Who Is This For?

Whether you're a professional mechanic, an avid DIYer, or working in an industrial setting, this bolt and nut gauge is the perfect pocket companion. Stop second-guessing thread sizes and start working with confidence every single time.

Pair It With These Tools

• 1/2" Drive Wheel Protector Impact Socket Set + Storage Case
• 10-Inch Carbon Steel Knife Sharpening Rod | Honing Steel
• 1/4" Hex Shank Wire Twister Drill Attachment | Rebar Tie Tool

For more information on fastener standards and measurement best practices, visit the National Institute of Standards and Technology (NIST) – Weights & Measures.

Frequently Asked Questions

Q: What measurement range does the bolt and nut size finder keychain cover?

A: The gauge covers a measurement range of 0–80 mm and includes both metric and imperial markings, making it suitable for the vast majority of standard bolts and nuts used in automotive, DIY, and industrial applications.

Q: What material is the bolt size gauge keychain made from?

A: It is made from high-quality stainless steel, giving it excellent durability and resistance to wear — ideal for regular use in workshops, garages, and on job sites.

Q: Can this tool be used for both professional mechanics and DIY home projects?

A: Absolutely. The portable keychain bolt gauge is designed for a wide range of users, from professional mechanics and industrial technicians to everyday DIY enthusiasts working on home improvement or woodworking projects.

Q: Does the bolt size finder require any batteries or calibration?

A: No batteries or calibration are needed. The engraved markings are permanent and ready to use straight out of the box — simply slide your bolt or nut into the appropriate slot for an instant size reading.