The part number **D38999/24JJ04AB** refers to a high-reliability circular connector built to military specifications (MIL-DTL-38999 Series III). These connectors are designed for harsh environments, commonly used in aerospace, defense, and marine applications. --- ### Part Number Breakdown The following table breaks down each segment of the part number according to the military standard: | Segment | Code | Description | | :--- | :--- | :--- | | **Series** | D38999/24 | MIL-DTL-38999 Series III, **Jam Nut Receptacle** | | **Material/Finish** | JJ | Composite shell, **Olive Drab Cadmium** over Electroless Nickel | | **Shell Size** | J | Shell size **25** (J is the code for 25) | | **Insert Arrangement** | 04 | Layout 25-04 (4 size 12 power contacts) | | **Contact Type** | A | **Pin (Male)** connector, but supplied **without contacts** | | **Polarization** | B | Alternate keying position "B" | --- ### Technical Specifications These components are engineered to withstand extreme physical and electrical stress. #### 1. Mechanical Properties * **Coupling:** Triple-start threaded coupling for quick and secure mating. * **Durability:** The composite shell (JJ) provides excellent corrosion resistance (up to 2000 hours of salt spray) and is significantly lighter than stainless steel. * **Vibration/Shock:** Designed to remain coupled under high-vibration scenarios (Sinu-soidal and Random). #### 2. Electrical Properties * **Contact Size:** Size 12 contacts are generally rated for approximately **23 Amps**. * **Configuration:** The "04" arrangement consists of 4 large power contacts, making this specific part suitable for power distribution rather than high-density signal transmission. * **EMI Shielding:** Provides 360° shell-to-shell continuity for electromagnetic interference protection. #### 3. Environmental Resistance * **Temperature Range:** Operates between **-65°C to +175°C**. * **Sealing:** Moisture resistant and capable of maintaining integrity at high altitudes. --- ### Important Note on "AB" Suffix In MIL-DTL-38999 nomenclature, the **"A"** in the penultimate position indicates a Pin connector, and the **"B"** in the final position usually refers to the Clocking/Keying. However, it is vital to note that when a part ends with "A" or "B" in the contact position (like ...04**A**B), it often signifies that the connector is being shipped **without the actual crimp contacts**. You must purchase the size 12 pins separately.