The Simpson Strong-Tie HDIA25SS Hollow Drop-In Internally Threaded Anchor is a flush-mount expansion anchor engineered by Simpson Strong-Tie for attaching threaded rod to support conduit, cables, and lighting across a wide range of base materials. Its versatile expansion design allows it to perform reliably in both hollow materials - such as CMU and hollow-core plank - and solid materials including brick, normal-weight concrete, and lightweight concrete, making it one of the most adaptable anchoring solutions available for overhead and suspension applications.

Key Features

• Suitable for suspending conduit, cable trays, pipe supports, fire sprinklers and suspended lighting into concrete
• Expansion design allows HDIA to anchor into CMU, hollow-core plank, brick, normal-weight concrete and lightweight concrete
• Internally threaded anchor allows for easy bolt removal
• Die-cast Zamac 3 alloy shell with Type 304 stainless-steel cone
• Flush-mount profile sits level with the surface for a clean, unobtrusive installation
• Compatible with standard threaded rod for straightforward attachment
• Install with HDIASTH25 setting tool for hollow materials or HDIASTS25 for solid materials

Specifications

• Model Number (MPN): HDIA25SS
• Length: 3/4 in.
• Rod Diameter: 1/4 in.
• Drill Bit Diameter: 3/8 in.
• Threads Per Inch (TPI): 20
• Shell Material: Die-cast Zamac 3 alloy
• Cone Material: Type 304 stainless steel
• Packaging: Packs of 100 and Cartons of 1600
• Country of Origin: China

Approved Applications

• Suspending conduit and electrical cable trays from overhead concrete ceilings
• Pipe support and mechanical systems attachment in concrete structures
• Fire sprinkler system installation requiring flush-mount anchoring
• Suspended lighting fixtures in both hollow and solid base materials
• Anchoring into CMU (concrete masonry unit) block walls and hollow-core plank
• Threaded rod attachment in normal-weight and lightweight concrete
• Brick substrate anchoring where a flush-mount expansion anchor is required

Frequently Asked Questions

What base materials is the HDIA25SS compatible with?

The HDIA25SS is designed for use in both hollow and solid base materials. Hollow material options include CMU and hollow-core plank, while solid material options include brick, normal-weight concrete, and lightweight concrete.

What size drill bit is required to install the HDIA25SS?

Installation requires a 3/8-inch diameter drill bit to create the proper hole for the anchor.

What setting tools are needed for installation?

The HDIA25SS requires a setting tool for proper installation. Use the HDIASTH25 setting tool for hollow base materials such as CMU and hollow-core plank, or the HDIASTS25 setting tool for solid base materials such as concrete and brick.

What threaded rod size is compatible with the HDIA25SS?

The HDIA25SS accepts a 1/4-inch diameter threaded rod with 20 threads per inch (TPI), making it suitable for standard 1/4-20 threaded rod commonly used in conduit, cable tray, and lighting suspension applications.

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