AutoLine Pro Smoke Machine 2-in-1 Cone & Cap Plug Adapters — CarbonNitrile, Stackable, Fits up to 3.75in (94mm)

AutoLine Pro Premium Cone and Plugs are dual-purpose adapters that let you inject smoke into larger openings and seal off escape points for fast, reliable automotive leak testing.

Built for mechanics, service shops, and DIY technicians, these patented CarbonNitrile™ 2-in-1 adapters combine a cone injector and cap-style plug into a single, stackable tool. They accommodate a wide range of hose and pipe diameters and are tough enough for repeated shop use while remaining compact for easy storage. Below you'll find clear answers to common questions about sizing, compatibility, durability, and practical use so you can decide quickly if these adapters fit your workflow.

How do these adapters simplify smoke machine leak testing?

The AutoLine Pro adapters merge two functions—injecting smoke and blocking escape paths—so you don’t need multiple tools. Using the cone to feed smoke into an opening while sealing other outlets speeds diagnostics and reduces fumbling with mismatched fittings.

• 2-in-1 design replaces separate injector cones and cap plugs.
• Quickly seal one tailpipe while introducing smoke in the other.
• Stackable shape keeps kits organized and reduces bench clutter.

What sizes and vehicle connections will these fit?

These adapters support a broad range of hose and tube diameters, covering common automotive sizes for versatile shop application. The tapered cone and cap geometry let you work with small lines and larger openings without forcing or modifying parts.

• Maximum opening fit up to 3.75" (94 mm).
• Minimum tube compatibility down to 0.125" (3.2 mm).
• Fits standard hose sizes like 1/8", 1/4", 3/8", 1/2", 3/4", 1" and more.

Are these compatible with dual tailpipe and exhaust testing?

Yes—designed specifically to work with OEM and most common 2" dual tailpipes. One tailpipe can be sealed while smoke is injected into the opposite side, creating a controlled path for diagnostics without makeshift adapters.

• Works with most 2" dual tailpipe configurations.
• Enables isolating one outlet while pressurizing the other with smoke.
• Reduces the need for clamps or improvised sealing materials.

How durable are these adapters and what warranty covers them?

The adapters are molded from CarbonNitrile™, a rugged elastomer chosen for tear resistance and long service life in shop environments. AutoLine Pro backs the product with a three-year warranty against manufacturing and operational defects, and replacement support is provided from within the United States.

• CarbonNitrile™ construction resists wear and repeated use.
• Patented profile designed for stacking and neat storage.
• Three-year warranty with prompt U.S.-based replacement service.

Who is this for? AutoLine Pro Premium Cone and Plugs are intended for professional technicians, mobile mechanics, and knowledgeable DIYers who perform smoke leak detection on a variety of vehicles. If you need a single, reliable adapter set that reduces tool swaps, fits common hose and exhaust sizes, and stands up to daily shop use, these adapters are a practical addition to your diagnostic kit.