
Master Lock 5406D
Score: 75/100
Master Lock 5440EC
Score: 85/100Rankings

The Master Lock 5440EC is a portable, smart key lock box designed for realtors and property managers who need flexible, temporary access control. Its key strength lies in its Bluetooth connectivity and app integration, allowing for tamper and low-battery alerts. While it lacks the permanent stability of wall-mount options, it is ideal for short-term rentals and property showings.

The Master Lock 5406D is a portable, over-the-knob key lock box featuring a durable metal body and a set-your-own 4-digit combination. It is designed for users who need a robust, cost-effective solution for temporary key storage without the need for smart features. It is best suited for real estate agents and homeowners who prioritize durability and portability over advanced connectivity.
| Attribute | ![]() | ![]() |
|---|---|---|
5 keysbest | 5 keysbest | |
13.34 cmbest | 12.2 cm | |
6.99 cm | 8.3 cmbest | |
3.81 cmbest | 2.9 cm | |
| ↓ lower better | 0.32 kgbest | 0.5 kg |
35.71 mm | 46 mmbest | |
— | 1 yearsbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Durability & Environment(1) | ||
Weather Resistance Rating | Yes, with weather cover | Weather resistant to -40° |
Installation & Mounting(1) | ||
Mounting Type | Portable, Over-the-knob | Portable over-the-knob |
Design & Fit(3) | ||
External Height (cm) | 13.34 cm | 12.2 cm |
External Width (cm) | 6.99 cm | 8.3 cm |
External Depth (cm) | 3.81 cm | 2.9 cm |
Build & Design(2) | ||
Body Material | Durable metal body with vinyl-coated shackle | Molded body with vinyl-coated shackle |
Product Weight (kg) | 0.32 kg | 0.5 kg |
Support & Warranty(1) | ||
Warranty Length (years) | Lifetime years | 1 years |
Security & Access(2) | ||
Lock Type | 4-digit numeric | 4-digit combination |
Shackle Length (mm) | 35.71 mm | 46 mm |


Products in the top-left offer the best value (high score, low price).

Sources lack dedicated expert reviews from major testing organizations. Manufacturer descriptions emphasize reliability for real estate and rentals, highlighting the anti-jamming cavity, weather protection, and portability as strengths for home and rental use.
Limited consumer feedback is available, with one noted 5-star review praising key capacity and ease of use. Common praise is inferred to center on the convenience of storing house keys and the portability of the device.

Master Lock's official descriptions characterize the 5400D as a reliable key safe for home or rental use, emphasizing its secure, keyless access and anti-jamming design.
Official notes imply user-friendly operation and convenience for rentals and real estate, suggesting positive reception for its intended temporary access use cases.

