onelinkmore SMA Pigtail Cable UFL to SMA Female Jack Coupling Nut Hole Bulkhead Straight O-Ring Coaxial Cable 1.13 Cable Pack of 2

The O-ring is a pre-installed rubber gasket that sits between the SMA female bulkhead body and the outer face of the enclosure panel. When the hex nut is tightened from inside the enclosure, it compresses the O-ring against the panel surface, creating a water-resistant seal around the connector mounting hole. No sealant tape or silicone is required — the O-ring provides the seal when properly torqued. The seal is effective against rain splash and condensation but is not rated for submersion; for fully submersible applications, additional sealing at the cable entry point is needed.

Measure the distance from your board's U.FL antenna port to the inside face of the enclosure wall where the SMA bulkhead will be mounted, then add approximately 20–30mm for routing slack and connector seating. Common selections: 1.96" (50mm) for very compact enclosures with the board mounted close to the wall; 3.93" (100mm) for standard small project boxes and gateway enclosures; 5.9" (150mm) for deeper enclosures or where the board is mounted away from the wall. Avoid choosing longer than necessary — excess cable must be coiled inside, which adds signal loss and clutter.

Yes, for Raspberry Pi modules and Arduino boards that have U.FL antenna ports — such as the Raspberry Pi Compute Module 4 with WiFi, or Arduino MKR modules with cellular connectivity. The U.FL connector snaps onto the board's U.FL port, and the SMA female bulkhead mounts through the project enclosure wall to accept a standard SMA male external antenna. Verify your specific board has a U.FL port (2.0mm) rather than an MHF4 port (1.5mm) before ordering.

Standard SMA female bulkhead connectors use a thin hex nut (approximately 6mm across flats) that provides a small contact area against the enclosure panel. Under repeated antenna connect-disconnect cycles or cable tension, this thin nut can work loose, rotating the connector body and eventually widening the mounting hole. The enlarged hex nut on this connector provides a wider bearing surface that is harder to loosen and distributes force more evenly across the panel face. For outdoor or high-vibration installations, this mechanical improvement significantly extends the reliable service life of the antenna mounting point.

Drill a hole in the enclosure wall sized for the SMA connector body — typically 6.5mm (approximately 1/4 inch) for standard SMA bulkhead connectors. Insert the SMA female end through the hole from outside to inside (so the O-ring is compressed between the connector body flange and the outer enclosure surface). From inside, slide the hex nut onto the threaded portion and tighten with a wrench until the O-ring is visibly compressed — approximately 1–2 turns past finger-tight. Do not overtighten, as this can damage the O-ring seal.

Many Mini PCIe wireless cards, cellular modules, and IoT gateway boards have two U.FL antenna ports for MIMO diversity — one main antenna and one auxiliary/diversity antenna. Building a properly sealed outdoor enclosure requires both ports to have weatherproof external connections. The 2-pack provides both cables needed for a complete dual-antenna enclosure build. Both cables are the same length (select the variant that matches your enclosure depth) for a symmetric installation.