
KeyGuard SL-500 Black
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 KeyGuard SL-500 is a portable punch-button lock box with a spacious interior and alphanumeric keypad for flexible code creation. Its main limitation is a somewhat complex setup process requiring precise button rotation. It is ideal for realtors and property managers needing temporary, portable key access.
| Attribute | ![]() | ![]() |
|---|---|---|
— | 5 keysbest | |
6.8 cm | 12.2 cmbest | |
2.1 cm | 8.3 cmbest | |
4 cmbest | 2.9 cm | |
| ↓ lower better | 0.45 kgbest | 0.5 kg |
— | 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 | weather_resistant | Weather resistant to -40° |
Installation & Mounting(1) | ||
Mounting Type | shackle | Portable over-the-knob |
Storage & Capacity(1) | ||
Key Capacity (keys) | unlimited keys | 5 keys |
Design & Fit(3) | ||
External Height (cm) | 6.80 cm | 12.2 cm |
External Width (cm) | 2.10 cm | 8.3 cm |
External Depth (cm) | 4.00 cm | 2.9 cm |
Build & Design(2) | ||
Body Material | metal_plastic_coating | Molded body with vinyl-coated shackle |
Product Weight (kg) | 0.45 kg | 0.5 kg |
Security & Access(2) | ||
Lock Type | pushbutton | 4-digit combination |
Shackle Length (mm) | unknown mm | 46 mm |


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

Professional reviewers praise the KeyGuard SL-500 for its superior storage capacity, intuitive phone-style keypad, and protective coating that prevents door scratches.
Demos simulate a positive user experience, noting the ease of fitting a handful of keys with space left over, but no recurring praise or complaints from actual buyers are documented.

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.

