AutoLine Pro Smoke Test Cone & Plugs 2-in-1 Kit, CarbonNitrile™ — Fits 0.125"–3.7", Dual‑Tailpipe Compatible

AutoLine Pro Premium Cone and Plugs are a patented 2-in-1 CarbonNitrile™ adapter set that lets technicians inject smoke into service openings and reliably seal other ports for accurate automotive leak testing.

When locating vacuum, intake, exhaust or body leaks with a smoke machine, having adapters that both introduce smoke and seal unwanted exits speeds diagnosis and reduces false positives. The AutoLine Pro Cone and Plugs pair a tapered injection cone with complementary cap plugs in a single stackable kit. Built from resilient CarbonNitrile™, these fittings accept tubes down to 0.125" (3.2mm) and expand to a 3.7" (94mm) maximum diameter to work with a broad range of hose sizes and factory openings.

How do these adapters make smoke testing faster and more accurate?

The 2-in-1 design lets you route smoke into a target opening while simultaneously sealing other escape routes, so you see the true leak source instead of diffuse vapor. The tapered cone allows controlled injection, and the cap plugs close off nearby ports that would otherwise misdirect smoke.

• Dual-function components for injection and sealing
• Tapered cone concentrates smoke delivery to the test area
• Cap plugs prevent smoke loss from adjacent openings
• Compatible with common shop hose sizes for quick setup

Which sizes and vehicle openings will these adapters fit?

These pieces accommodate a broad size range: minimum tube entry of 0.125" (3.2mm) up to a maximum outer diameter of 3.7" (94mm). That makes them suitable for intake boots, vacuum lines, evap ports, and many service openings found on passenger cars, trucks, and SUVs.

• Fits tubing 1/8", 1/4", 3/8", 1/2", 3/4", 1" and other common sizes
• Maximum cone diameter 3.7" (94mm) for larger openings
• Min tube hole accepts 0.125" (3.2mm) for fine hose connections
• Works with plastic and rubber service ports without damage

Can these be used with dual tailpipes and exhaust leak checks?

The set includes shapes designed to match OEM-standard and most common 2" dual tailpipes. By plugging one tailpipe and injecting smoke into the other, you can quickly determine whether exhaust leaks originate in the muffler, piping, or flange joints.

• Dual-tailpipe compatible, fits most 2" exhaust openings
• Allows one-pipe block and the other for smoke injection testing
• Seals snugly to limit smoke escape and improve visual detection
• Durable under repeated contact with hot or dirty components

What makes CarbonNitrile™ and the patented design better for shops?

CarbonNitrile™ offers high resilience to wear, repeated compressions, and shop contaminants, extending service life versus ordinary rubber adapters. The patented geometry stacks for compact storage and resists deformation so the fittings retain a reliable seal over time.

• CarbonNitrile™ resists cracking, tearing, and fuel/oil exposure
• Patented stacking saves bench and toolbox space
• Maintains consistent sealing profile through repeated use
• Backed by a straightforward three-year warranty

Who is this for: AutoLine Pro Premium Cone and Plugs are geared to professional mechanics, independent diagnostic shops, and serious DIYers who perform routine smoke leak checks on engines, intake systems, vacuum networks, EV HVAC components, and exhaust systems. If you need durable, reusable adapters that speed up diagnosis and reduce ambiguous smoke results, this kit is designed to fit a wide range of vehicle service scenarios and will withstand heavy shop use.