STI STI-3100 Clear Conduit Spacer for Stopper II

Overview

The STI STI-3100 is a clear conduit spacer engineered for use with STI Stopper II lock and strike assemblies. This accessory maintains proper spacing and alignment within conduit runs, eliminating mechanical bind and electrical contact issues that arise when components sit flush or misaligned. For security integrators deploying electronic locks and strikes in dense installations, correct spacing prevents costly field callbacks and rework.

Key Features

• Clear Construction: Transparent design lets you verify internal alignment visually before final installation—no guessing whether the striker plate and latch are co-planar. Saves troubleshooting time on multi-door rollouts.
• 9VDC Compatibility: Works with standard Stopper II strike voltage. Paired with low-power solenoid strikes, the spacer ensures no mechanical drag that would draw excess current and stress your access control power supply.
• Precise Positioning: Maintains consistent gap between frame and strike assembly. Prevents the slight misalignments that cause intermittent electrical contact or solenoid chatter under door movement—reliability matters in high-traffic or secure entry points.
• Conduit Integration: Designed for routing through standard electrical conduit. Simplifies raceway planning and keeps your installation clean when door frames have irregular mounting surfaces or when you need to transition between different frame depths (aluminum, steel, composite).

Integration & Compatibility

The STI-3100 is a direct fit for the Stopper II family. Confirm your strike model carries the Stopper II designation before ordering. Use this spacer in any installation where door frame geometry or adjacent hardware (closers, hinges) limits direct mounting—common in retrofit scenarios where new electronic strikes mount onto older or non-standard frames.

Compatible with 9VDC access control power supplies standard in most mid-sized integrations. Pair with proper strike voltage planning to avoid under-spec'd supplies that would cause solenoid dropout under peak load.

Frequently Asked Questions

Q: Is the STI-3100 required for every Stopper II installation?

A: No. Use the spacer only when frame geometry, mounting hardware, or conduit routing prevents flush mounting. Standard surface-mounted installations without geometric constraints do not need it.

Q: What thickness does the STI-3100 provide?

A: Specific thickness is not detailed in the available documentation. Refer to the manufacturer datasheet or contact STI technical support to confirm the exact spacing offset for your frame type.

Q: Can the STI-3100 be used with other strike brands?

A: No. This spacer is engineered specifically for the Stopper II series. Using it with non-compatible strikes may result in misalignment and reliability issues.

Q: Does the clear material degrade in sunlight or high-temperature environments?

A: Material durability under extended UV or temperature extremes is not specified in the documentation. For outdoor or high-temperature applications, confirm material compatibility with STI before deployment.

Ted Perry

Perspective based on aggregated IP Security Depot and affiliated engineering team experience.

The STI-3100 is a straightforward but often overlooked spacer that solves real field problems in access control deployments. When a Stopper II strike won't sit flush due to frame irregularities or conduit routing constraints, the clear construction of the STI-3100 lets you verify alignment before final wiring—critical when you're troubleshooting a 50-door retrofit and can't afford intermittent electrical contact failures.

Technical Highlights:

• 9VDC Rated: Works with standard solenoid strike voltage. Ensures no mechanical binding that would spike inrush current and stress your power supply under repeated operation.
• Clear Material: Transparency eliminates guesswork on internal component alignment. Prevents hidden misalignment that would only surface after the door frame is finished.
• Stopper II Specific Design: Precision fit for the Stopper II family—not a universal spacer. Cross-compatibility with other strikes will introduce alignment error and solenoid reliability issues.

Deployment Considerations:

• Confirm your frame geometry actually requires spacing before ordering. Most standard surface-mount installations do not. Unnecessary spacers add cost and assembly steps.
• The material composition and UV durability are not documented. If your installation has outdoor exposure or extreme temperature swings, contact STI to verify material performance before committing to a large job.

Use the STI-3100 in retrofit and specialty-frame scenarios—retrofit apartments with steel frames, commercial spaces with atypical door hardware, or conduit-routed installations where flush mounting is geometrically impossible. For new construction with standard aluminum frames and direct strike mounting, it's unnecessary.