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

The PL-259 connector is the most widespread RF connector used in amateur radio for High Frequency (HF) and Very High Frequency (VHF) applications. It is rugged, easy to solder, and perfectly adequate for frequencies up to about 148 MHz, where its slight impedance mismatch is negligible. Despite being historically named the 'UHF connector' in the 1930s, the PL-259 is not preferred for microwave or modern UHF operation because it does not maintain a constant 50-ohm impedance. Additionally, it is a threaded connector (unlike the bayonet-style BNC) and is completely unsealed, meaning it is not watertight and requires heavy weatherproofing if used outdoors.