Olsa Tools Bolt Size Finder Keychain

This slim, pocket-ready tool eliminates guesswork when matching sockets, nuts, or fittings. Built with a dual-sided layout for Metric and SAE, the Olsa Tools Bolt Size Finder fits on a keyring and functions like a small, rugged caliper—so you can confirm sizes without trial-and-error or digging through a toolbox. It’s designed for everyday carry by mechanics, DIYers, and anyone who frequently works with fasteners or parts.

How will this keychain gauge speed up my work?

Instead of repeatedly testing sockets or measuring with bulky tools, this gauge gives an immediate size match. That reduces time spent switching bits or returning to the shop for the right tool. It’s especially useful on jobs where multiple fastener standards are encountered.

• Instant size identification for Metric and SAE fasteners.
• Reduces socket trial-fitting and tool swapping.
• Portable on a keyring—ready wherever you go.

What range and accuracy can I expect from the gauge?

The plated metal keychain covers Metric sizes from 8mm up to 25mm and SAE sizes from 5/16" to 1". Each stamped opening is sized to seat a bolt head or nut cleanly so you can visually confirm the match. It’s not a laboratory instrument, but it offers practical accuracy for workshop and field use.

• Metric coverage: 8mm–25mm for common automotive and household fasteners.
• SAE coverage: 5/16"–1" for imperial applications.
• Durable metal construction for repeatable sizing checks.

Can this tool do more than measure bolts?

Yes—the design works like a quick visual caliper for other small parts. Use it to estimate hose fittings, spare threaded parts, or small hardware when you need a fast reference. The compact profile means you can carry it with keys or in a pocket without adding bulk.

• Useful for hose swivel, nut, and small fitting checks.
• Acts as a quick reference when ordering replacement parts.
• Attaches to a keyring so it’s available at the job site.

Who is this for? If you’re a professional mechanic, a weekend wrench, a bicycle or appliance tinkerer, or someone who frequently matches fasteners, the Olsa Tools Bolt Size Finder Keychain is a practical addition to your EDC. It’s also an affordable gift for tool lovers—small enough to carry always, robust enough for regular shop use, and clear enough to cut down on frustrating size swaps.