What this BNC adapter is and what it does
The TE Connectivity 221551-1 is a straight BNC jack-to-jack adapter — a female-to-female barrel coupler that lets you join two BNC male-terminated cables end-to-end. It is a same-series adapter (BNC to BNC), so there is no impedance or interface conversion; it simply extends or bridges a BNC signal path. Rated at 50 Ohms impedance, this adapter is built for standard 50 Ohm BNC systems — test equipment, instrumentation, RF lab setups, and video distribution where the characteristic impedance of the cable and connectors match. The PTFE dielectric keeps the impedance stable across frequency and temperature, and the silver-plated phosphor bronze center contacts give low and repeatable contact resistance through multiple mate cycles. The body carries a nickel finish — standard for commercial BNC hardware, providing corrosion resistance that holds up in indoor lab, bench, and field-service environments. Both ends use a bayonet lock (quarter-turn, no tools), so you can mate or break the connection quickly without unscrewing anything. This is a free-hanging (in-line) adapter — it is not designed for panel or bulkhead mounting. It sits between two cable assemblies, making it the right choice for extending a coax run or converting a male-to-male connection into a male-to-female one at the adapter midpoint.
Impedance and signal-path fit
This adapter is rated at 50 Ohms impedance, matching standard 50 Ohm BNC systems. The straight body style keeps the signal path straight through the adapter.