Which of the following is true of PL-259 type coax connectors?

The PL-259 (plug) and its mating SO-239 (socket) are historically known as "UHF connectors." Despite this name, their non-constant impedance makes them lossy at higher frequencies, so they are primarily used in modern amateur radio for HF (High Frequency) and VHF (Very High Frequency) applications where those losses are negligible. These connectors are threaded, not bayonet-type (which describes BNC connectors). Furthermore, they are notably not watertight; they require external waterproofing like self-vulcanizing tape when used outdoors to prevent moisture from entering and ruining the coaxial cable.