SMC KQ2S16-04S Hex Socket Male Connector Push-In Fitting — KQ2 Series Ø16mm Tube Rc1/2 Thread With Sealant
2026-05-28Product Overview
The SMC KQ2S16-04S is a hex socket head male connector from SMC’s KQ2 Series One-Touch Fittings, designed for push-in pneumatic tubing connections. It accepts Ø16mm OD tubing and features an Rc1/2 (BSPT) male thread with thread sealant pre-applied (suffix “S”), enabling a leak-free seal without additional sealing tape in most applications.
SMC KQ2 Series push-in fittings are among the most widely used pneumatic connection components worldwide, recognized for their tool-free tube insertion, reliable one-touch release, and compact white nylon body. The KQ2S hex socket body design allows easy installation and removal using a standard hex key, making it ideal for tight installation spaces where a wrench cannot reach.
Compatible with SMC tubing series including TU, TS, and TIA, the KQ2S16-04S is suitable for compressed air systems operating in industrial automation, food processing, semiconductor manufacturing, and general factory environments.
Product Specifications
| Parameter | Specification |
|---|---|
| Part Number | KQ2S16-04S |
| Series | KQ2 — One-Touch Push-In Fittings |
| Fitting Type | Male Connector, Hex Socket Head (Type S) |
| Applicable Tube O.D. | Ø16 mm |
| Male Thread Size | Rc1/2 (BSPT, bore Ø4 — port size code 04) |
| Thread Sealant | Pre-applied (suffix S — With Thread Sealant) |
| Body Color | White (body) / Light gray (release button) |
| Body Material | PBT resin (reinforced nylon) |
| Seal Material | NBR (nitrile rubber) |
| Operating Fluid | Air, Inert Gas (non-corrosive) |
| Max. Operating Pressure | 1.0 MPa (at 20°C) |
| Operating Temperature | 0 ~ 60°C |
| Vacuum | Applicable (confirm tube compatibility) |
| Standard | KQ2-E: One-touch Fittings Catalog |
Part Number Breakdown
Understanding the SMC KQ2 series naming convention:
- KQ2 — KQ2 Series One-Touch Push-In Fitting
- S — Fitting type: Hex Socket Head Male Connector
- 16 — Applicable tube O.D.: Ø16 mm
- 04 — Male thread port size: Rc1/2 (BSPT) / NPT1/2
- S (suffix) — With pre-applied thread sealant on male threads
Other common KQ2 type codes: H = Male Connector, L = Male Elbow, ZT = Union Tee, E = Bulkhead Connector, U = Union Y, F = Female Connector.
Key Features
- Tool-free tube connection: Push the tube straight in — the internal collet grips and seals instantly. One-touch release by pressing the gray release button.
- Pre-applied thread sealant: The “-S” suffix means male threads come pre-coated, reducing assembly time and risk of missing tape on site.
- Hex socket body: Allows installation with a hex wrench in confined panel spaces, DIN rail enclosures, or manifold blocks.
- High pressure rating: 1.0 MPa working pressure suitable for the majority of industrial pneumatic circuits.
- Wide tube compatibility: Works with SMC TU (polyurethane), TS (soft nylon), and hard nylon tubing in Ø16mm OD.
Typical Applications
- Industrial Automation: Connecting Ø16mm air lines to pneumatic cylinders, actuators, and valves in assembly machines and conveyors.
- Robotics & Handling: Air supply connections to end-of-arm tooling (EOAT) and vacuum gripper manifolds where compact installation is critical.
- Semiconductor & Electronics: Clean-room compatible pneumatic circuits requiring secure, particle-free tube connections.
- Packaging Machinery: High-cycle pneumatic systems in form-fill-seal and cartoning equipment where reliable tube retention is essential.
- Food & Beverage Equipment: Compressed air distribution in washdown-tolerant environments (verify fluid compatibility with body material).
Frequently Asked Questions
Q: Can I use KQ2S16-04S with polyurethane (PU) tubing?
A: Yes. SMC KQ2 fittings are compatible with SMC TU series polyurethane tubing (Ø16mm OD). Ensure the tube end is cut cleanly and squarely before inserting. Avoid using tubing with an outer diameter tolerance beyond ±0.1mm for reliable sealing.
Q: Does the “-S” sealant work for all thread materials and pressures?
A: The pre-applied SMC thread sealant is designed for Rc (BSPT) threaded connections in compressed air service up to 1.0 MPa. For steam, hydraulics, or chemical service, consult SMC’s engineering team before use.
Q: What is the difference between KQ2S16-04S and KQ2S16-04A?
A: The “-04S” suffix indicates Rc (BSPT) thread with pre-applied sealant, while “-04A” denotes NPT thread. Select based on the thread standard used in your installation (Rc is common in Asia/Europe; NPT in North America).
Q: Can KQ2S16-04S be used in vacuum applications?
A: Yes, KQ2 series fittings are generally suitable for vacuum service. However, confirm the tube type and fitting seal integrity at your target vacuum level. For high-vacuum systems, SMC recommends dedicated vacuum-rated fittings.
SMC KQ2 Series One-Touch Fitting — Related Part Numbers
The following SMC KQ2 series part numbers represent the broad range of push-in fitting configurations, tube sizes, and thread options available. Listed for reference and cross-selection:
- KQ2S16-03A — Hex Socket Male Connector, Ø16mm, 03A
- KQ2H05-02NS1 — Male Connector, Ø05mm
- KQ2L07-U01-X2 — Male Elbow, Ø07mm
- KQ2W12-U03A — Branching Y, Ø12mm
- KQ2W10-U04A — Branching Y, Ø10mm
- KQ2H08-01 — Male Connector, Ø08mm, Rc1/8
- KQ2T11-35S-X2 — Union Tee, Ø11mm
- KQ2C-06A-YR — Cap
- KQ2L13-37A — Male Elbow, Ø13mm, 37A
- KQ2F12-04-X2 — Female Connector, Ø12mm
- KQ2L04-01S-X44 — Male Elbow, Ø04mm
- KQ2VF09-35AS — Reducer, Ø09mm
- KQ2T04-01NS1 — Union Tee, Ø04mm
- KQ2H04-00A-X35 — Male Connector, Ø04mm
- KQ2L06-01A — Male Elbow, Ø06mm, NPT1/8
- KQ2H07-M5A — Male Connector, Ø07mm
- KQ2LU04-M5 — Male Elbow, Ø04mm
- KQ2S10-03AP — Hex Socket Male Connector, Ø10mm
- KQ2L07-32-X2 — Male Elbow, Ø07mm
- KQ2U08-03AP — Union Y, Ø08mm
- KQ2C-08GRA — Cap
- KQ2Y08-02S — KQ2 Push-in Fitting, Ø08mm
- KQ2K08-01AS — Male Run Tee, Ø08mm
- KQ2E06-00N1 — Bulkhead Connector, Ø06mm
- KQ2UD06-02GS — Union Y, Ø06mm
- KQ2H01-07A — Male Connector, Ø01mm
- KQ2VD04-02AS1 — Reducer, Ø04mm
- KQ2H12-U03A — Male Connector, Ø12mm
- KQ2T06-08A1 — Union Tee, Ø06mm
- KQ2V06-02 — Reducer, Ø06mm, Rc1/4
- KQ2H06-U02N — Male Connector, Ø06mm
- KQ2VS09-35NS — Reducer, Ø09mm
- KQ2L16-03GS — Male Elbow, Ø16mm
- KQ2L13-00 — Male Elbow, Ø13mm
- KQ2L08-01AQS — Male Elbow, Ø08mm
- KQ2F07-35 — Female Connector, Ø07mm
- KQ2H12-03NP — Male Connector, Ø12mm
- KQ2L10-U01A — Male Elbow, Ø10mm
- KQ2L09-02AP — Male Elbow, Ø09mm
- KQ2H08-10A-X35 — Male Connector, Ø08mm
- KQ2C-10G — Cap
- KQ2S04-U01A — Hex Socket Male Connector, Ø04mm
- KQ2F09-34A — Female Connector, Ø09mm
- KQ2L06-99A — Male Elbow, Ø06mm
- KQ2ZD12-02NS — Union Straight, Ø12mm
- KQ2Y12-02S — KQ2 Push-in Fitting, Ø12mm
- KQ2Y06-02AS-X35 — KQ2 Push-in Fitting, Ø06mm
- KQ2U10-03AS — Union Y, Ø10mm
- KQ2H04-M5N — Male Connector, Ø04mm
- KQ2R11-13 — KQ2 Push-in Fitting, Ø11mm
- KQ2V10-02AS-X35 — Reducer, Ø10mm
- KQ2H05-00A — Male Connector, Ø05mm
- KQ2E16-03A — Bulkhead Connector, Ø16mm
- KQ2S11-35AS — Hex Socket Male Connector, Ø11mm
- KQ2S10-03GS — Hex Socket Male Connector, Ø10mm
- KQ2L06-02NS — Male Elbow, Ø06mm
- KQ2L04-01-X2 — Male Elbow, Ø04mm
- KQ2H12-G03A — Male Connector, Ø12mm
- KQ2H10-01S-X44 — Male Connector, Ø10mm
- KQ2D04-M5N — KQ2 Push-in Fitting, Ø04mm
- KQ2T16-U03 — Union Tee, Ø16mm
- KQ2F07-32N — Female Connector, Ø07mm
- KQ2ZT06-02S — Union Tee, Ø06mm
- KQ2ZT04-02A — Union Tee, Ø04mm, NPT1/4
- KQ2W06-M5N — Branching Y, Ø06mm
- KQ2LU04-01NS — Male Elbow, Ø04mm
- KQ2H12-U04-X2 — Male Connector, Ø12mm
- KQ2C-11G — Cap
- KQ2VT12-04S-X2 — Reducer, Ø12mm
- KQ2R11-13A — KQ2 Push-in Fitting, Ø11mm
- KQ2L09-36S — Male Elbow, Ø09mm
- KQ2Y07-U01 — KQ2 Push-in Fitting, Ø07mm
- KQ2H04-06-X29 — Male Connector, Ø04mm
- KQ2S04-M6A — Hex Socket Male Connector, Ø04mm
- KQ2C-16BUA — Cap
- KQ2L04-M5N1 — Male Elbow, Ø04mm
- KQ2H06-02S-P — Male Connector, Ø06mm
- KQ2D12-04AS — KQ2 Push-in Fitting, Ø12mm
- KQ2VS03-32N — Reducer, Ø03mm
All models above belong to the SMC KQ2 One-Touch Push-In Fitting series. Contact us for pricing, availability, and bulk order enquiries.