The Simpson Drop-In Internally Threaded Anchor DIAB25 is a displacement-controlled expansion anchor from Simpson engineered for fast, reliable anchoring of 1/4-in. threaded rod into concrete and masonry base materials. Featuring improved geometry for smooth and accurate installation, this internally threaded drop-in anchor is redesigned to set with 40% fewer hammer hits than previous drop-in anchor designs - reducing labor effort and speeding up high-volume fastening work. A built-in positive-set marking system confirms proper placement at a glance, so installers can move confidently from one anchor to the next without guesswork.

Key Features

• Sets with 40% fewer hammer hits than previous drop-in anchor design - faster installation means less fatigue and more anchors set per shift on demanding concrete fastening jobs.
• Positive-set marking system - a visual indicator confirms the anchor is properly set, eliminating guesswork and reducing the risk of under-set anchors in the field.
• Displacement-controlled expansion - the anchor expands as the setting tool drives the plug toward the bottom, producing a consistent, reliable hold in concrete base materials every time.
• Zinc-plated carbon steel construction - provides a corrosion-resistant finish suited for interior concrete and masonry anchoring applications.
• Compatible with dedicated Simpson setting tools - installs with DIABST hand-setting tool model DIABST25 or power-setting tool model DIABST25-SDS, keeping installation method consistent and controlled.

Why This Product

• Engineered for speed without sacrificing accuracy - the improved anchor geometry and reduced hammer-hit requirement make this drop-in anchor a practical choice for contractors and crews running high volumes of concrete anchoring tasks where installation time directly affects project costs.
• Foolproof confirmation built in - the positive-set marking system means every installer on a crew - regardless of experience level - gets a clear signal that the anchor is correctly seated, helping maintain consistent quality across a job site.
• Designed for 1/4-in. threaded rod applications - the precise internal threading at 20 TPI accepts standard 1/4-in. rod, making this anchor a straightforward fit for common suspended ceiling, mechanical, and light structural anchoring tasks in concrete.
• A trusted Simpson design backed by improved engineering - this is not a first-generation product; Simpson refined the DIAB geometry specifically to address the installation challenges of earlier drop-in anchor designs, giving buyers a field-tested solution with measurable performance gains.

Specifications

• MPN: DIAB25
• Brand: Simpson Strong-Tie
• Material: Carbon Steel
• Coating / Finish: Zinc Plated
• Length: 1 in.
• Rod / Bolt Diameter: 1/4 in.
• Drill Bit Diameter: 3/8 in.
• Thread Length: 3/8 in.
• TPI: 20
• Packaging: Packs of 100 and Cartons of 500

Frequently Asked Questions

What size threaded rod does the DIAB25 accept?

The DIAB25 is designed to accept 1/4-in. diameter threaded rod, with 20 threads per inch (TPI) for a secure, compatible fit.

What drill bit size is required to install the DIAB25?

A 3/8-in. diameter drill bit is required to bore the correct hole for proper installation of the DIAB25 drop-in anchor.

How do I know when the DIAB25 anchor is properly set?

The DIAB25 features a positive-set marking system - a visual indicator at the top of the anchor that confirms when proper installation has taken place, eliminating guesswork during installation.

What tools are used to install the DIAB25?

The DIAB25 installs with DIABST hand-setting tool model DIABST25 or power-setting tool model DIABST25-SDS, both of which drive the expansion plug toward the bottom of the anchor for a displacement-controlled set.

Note: Product dimensions may differ from picture. Please see item description for specifications.