SMB Snap-On Plug for RG-174 Family — 4 GHz, 50 Ohm
It is a field-terminable kit — the bulk package includes all five pieces needed for one complete assembly: the connector body, the center contact, the ferrule, the insulator, and the rear body.
The 4 GHz frequency ceiling and 0.3 dB insertion loss define this connector's usable bandwidth for clean signal transfer. At 4 GHz, a 0.3 dB loss per mated pair is low enough that a single interconnect in a cable run will not dominate the link budget — it is the kind of performance you expect from a well-made SMB interface with a PTFE dielectric.
Cable Compatibility and Field Assembly — What's in the Kit
The 903-370P-51S is built for the RG-174 family — RG-174, 179, 187, 188, and 316 — all of which share a similar outer diameter and dielectric size. The shield termination is crimp, the center contact is solder. The kit approach (connector body, contact, ferrule, insulator, rear body) means you have everything except the cable and tools to make one cable assembly.
How This Compares to the Gold-Body 142194
Both are 50 Ohm, single-port SMB plugs for RG-174-family cables, with 500 mating cycles and crimp shield / solder contact termination. The meaningful difference is in the body finish and insertion loss: the 142194 uses a gold body finish (vs nickel on the 903-370P-51S) and has a higher insertion loss of 0.6 dB (vs 0.3 dB). Gold body finish gives better corrosion resistance in humid or outdoor-adjacent environments, but the 0.3 dB loss advantage of the 903-370P-51S makes it the cleaner choice for signal-path-sensitive applications where every tenth of a dB matters. The 142194 also ships as a 4-piece kit (no insulator listed separately) and includes a heat shrink instead of a rear body — a different assembly workflow.