Review on Absolute USA SPL2218R 22/18 Gauge Scotchlock Quick Splide Auto-TAP Connectors: Excelling in Secure and Fast Wire Connections by Allen Hart

It's just a metal connector that prestresses the insulation of the two wires that fit inside and a plastic case, so I don't see the need to buy more expensive ones. Haven't tested the connection with a continuity tester yet, but the connection looks solid. You can fill the cavity with silicone grease which can probably make it weather resistant like these wire connector type knobs. Pliers require some strength. It is designed to be squeezed with ordinary pliers or slip-joint pliers, which have more mechanical advantages. The cap is meant to be pushed in only and prevents the metal connector from shorting to other metals. It's not for squeezing a metal fork.