Based on the part number **1727184121**, this identifies a specific electronic component from the **Molex** Mini-Fit Family. It is a high-density power connector housing designed for wire-to-board or wire-to-wire applications. --- ### 1. Component Overview The **172718-4121** is a **Mini-Fit TPA2 (Terminal Position Assurance)** receptacle housing. The TPA feature is critical because it ensures that the crimped terminals are fully seated and prevents them from "backing out" under high vibration. ### 2. Technical Specifications | Feature | Specification | | :--- | :--- | | **Manufacturer** | Molex | | **Series** | Mini-Fit TPA2 (Series 172718) | | **Number of Circuits** | 21 Circuits | | **Number of Rows** | 2 Rows | | **Pitch (Mating Interface)** | 4.20 mm | | **Material** | Nylon (UL 94V-0 Rated) | | **Color** | Black | | **Operating Temp** | -40°C to +105°C | --- ### 3. Key Features & Benefits * **Terminal Position Assurance (TPA):** Compatible with a TPA retainer (sold separately) that locks the terminals in place. * **Polarization:** The housing is keyed to prevent accidental mis-mating with the wrong header. * **Positive Locking:** Features an integrated thumb latch that provides an audible "click" when the connection is secure. * **High Current Density:** Capable of handling high amperage relative to its small footprint, typically used in power supply units. ### 4. Common Applications This part is widely used in industrial, automotive, and consumer electronics, specifically: * **PC Power Supplies:** ATX power connectors. * **Home Appliances:** Control panels and internal wiring. * **Industrial Automation:** Sensor and actuator power distribution. * **Automotive:** Non-sealed internal cabin electronics. ### 5. Related Accessories To create a functional assembly, you would typically need: 1. **Female Terminals:** Series 172718 or 5556. 2. **TPA Retainer:** Series 172709. 3. **Mating Header:** Mini-Fit Jr. or Mini-Fit TPA2 headers (e.g., Series 5566, 5569). ---