These are **closed-end crimp wire connectors** (also called **closed-end wire caps** or **crimp caps**). **What they are:** * Translucent nylon outer sleeve * Metal crimp insert inside * One end closed, the other open for wires **What they’re used for:** * Joining **two or more electrical wires** together * Sealing the wire ends so no copper is exposed * Common in **automotive wiring, appliances, HVAC, control panels**, and low-voltage electrical work **How they work:** 1. Insert stripped wire ends into the open side 2. Crimp with pliers or a crimping tool 3. The metal core grips the wires; the nylon insulates and protects