SALSBURY C3390 National Mailbox Lock Cbu Specification

( Brand: Salsbury ), ( Manufacturer Part Number: C3390 ), ( Model: NATIONAL C3390 ), ( Type: Mailbox ), ( Security: Locking )

Review SALSBURY National Mailbox Lock Replacement Cbu Specification

The **Salsbury C3390 National Mailbox Lock** is a robust, high-security solution designed to protect residential and commercial mailboxes from unauthorized access while maintaining compliance with the **National Mailbox Association (NMA) standards**. Engineered with precision and durability in mind, this lock features a **CBU (Combination Bolt Unit) mechanism**, ensuring seamless integration with existing mailbox systems while delivering unparalleled security. Constructed from **heavy-duty steel**, the lock is built to withstand tampering, weather exposure, and frequent use, making it ideal for both urban and suburban environments where mailbox security is a priority. Its **smooth-operating combination dial** allows for quick and easy access for authorized personnel, while the reinforced locking mechanism prevents forced entry, including attempts with bolt cutters or lock picks. The C3390 is specifically designed to meet the **NMA s strict specifications**, ensuring compatibility with standard mailbox frames and doors, whether they are part of a residential cluster or a commercial mail center. The lock s **weather-resistant finish** guards against rust and corrosion, ensuring long-term reliability even in harsh climates, while its **low-maintenance design** minimizes wear and tear over time. Whether installed on a single-family mailbox or a multi-unit apartment complex, the Salsbury C3390 provides a reliable barrier against mail theft, vandalism, and unauthorized access, making it a trusted choice for property managers, homeowners, and postal service providers alike. Its **modular construction** also allows for easy installation and replacement, reducing downtime and ensuring a secure mail delivery system for years to come.

### **Pros and Cons of buying a Salsbury C3390 National Mailbox Lock (CBU Specification)**

1. **High Security** The C3390 is designed to meet the **National Mailbox Security Standards (NMSS)**, making it resistant to common tampering methods like bolt cutters, pry bars, and lock picks. It features a **high-security locking mechanism** with a hardened steel core and reinforced construction.

2. **Durable Construction** Made from **galvanized steel**, this lock is built to withstand harsh weather conditions, including rain, snow, and extreme temperatures. The **heavy-duty housing** ensures long-term reliability.

3. **Compliance with Industry Standards** The **CBU (Commercial Business Unit) specification** indicates it meets **USPS and postal service requirements**, ensuring compatibility with standard mailbox installations.

4. **Easy Installation** Designed for **quick and secure mounting**, the lock can be installed on most **standard residential and commercial mailboxes** without requiring extensive modifications.

5. **Low Maintenance** Due to its robust materials and weather-resistant design, it requires minimal upkeep, reducing long-term costs.

6. **Widely Available & Trusted Brand** Salsbury is a well-known manufacturer in the mailbox and security industry, meaning parts and replacements are easily accessible if needed.

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1. **Cost** Compared to basic mailbox locks, the C3390 is **more expensive** due to its high-security features. It may not be the most budget-friendly option for those with limited security needs.

2. **Limited Customization** Unlike some aftermarket locks, the C3390 is designed for **standard mailbox installations** and may not fit non-standard or older mailbox models without modifications.

3. **Potential Overkill for Low-Risk Areas** If you live in a **low-theft neighborhood**, a simpler lock might suffice, making this a **premium investment** for minimal additional security.

4. **Installation Complexity (For DIYers)** While generally straightforward, improper installation (e.g., misalignment or weak mounting) could compromise security. Professional installation may be recommended for optimal performance.

5. **Weight & Bulk** The heavy-duty construction means the lock is **larger and heavier** than basic models, which could be a consideration if aesthetics or space are a concern.

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### **Conclusion**

The **Salsbury C3390 National Mailbox Lock (CBU Specification)** is one of the **most secure mailbox locks available**, making it an excellent choice for **high-security residential, commercial, or business mailboxes**. Its compliance with **USPS and NMSS standards**, durability, and resistance to tampering justify its higher cost for those prioritizing **maximum protection**.

However, if **budget constraints** or **minimal security needs** are a concern, a **less expensive but still secure alternative** (such as a **Salsbury C3300 or a high-quality aftermarket lock**) might be sufficient. For most **urban or high-risk areas**, the C3390 is a **strong recommendation** due to its **proven reliability and industry compliance**.

- You need **maximum security** for a mailbox in a high-theft area.

- You require **USPS-compliant** or **commercial-grade** protection.

- You are willing to invest in **long-term durability** and **low maintenance**.

- You are on a **tight budget** and can accept a slightly lower security level.

- Your mailbox is **non-standard**, and compatibility is uncertain.

- You live in a **low-crime area** where basic locks would suffice.

Details:

Replacement for USPS F specifications on outdoor CBU mailboxes New bulk - no packaging. Keyed different Includes 3 keys, mounting clip, cam plate, and plate nut as seen in photo Dust/rain shield for weather protection photo.

part #: c3390 prices

• $115.00-$159.22

specifications mailboxesio:

• brand: Salsbury
• mpn: C3390
• model: National C3390
• type: Mailbox
• security: Locking

general mailboxesio:

• Building Hardware > Mailboxes, Slots Hardware > Mailboxes Slots
• condition: New

seller mailboxesio:

• rating: 99.9%
• # reviews: 32911
• city: Syracuse, New York

offer mailboxesio:

• quantity: 1
• started: May 28, 2026
• options: Ship-to-home
• sold: 0
• availability: In Stock

returns mailboxesio:

• method: Money back
• time: 30 Days
• paid by: Buyer
• policy: Returns Accepted

payments mailboxesio:

• other
• wallet: Paypal
• credit card: Discover

shipping mailboxesio:

• cost: $0.00
• type: Calculated
• transit: 4-8 Days
• class: Standard, Expedited, One-day
• carrier: USPS, FedEx, UPS
• service: USPS First Class, FedEx 2Day, UPS Ground, UPS Next Day Air Saver

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