
KeyGuard SL-590
Score: 80/100
Master Lock 5422E
Score: 65/100Rankings

The KeyGuard SL-590 is a wall-mounted, weather-resistant key storage lock box with a heavy-duty metal frame and large capacity for up to 8 keys. Its primary drawback is the risk of permanent lockout if the combination is forgotten. It is well-suited for realtors and property managers needing secure, fixed key access.

The Master Lock 5422E is a portable, push-button key lock box designed for quick, tool-free installation on door knobs. While it offers excellent usability with its touch interface and weather protection, it suffers from a critical security vulnerability where the lock can be decoded. It is best suited for low-risk, temporary access scenarios where convenience outweighs high-security needs.
| Attribute | ![]() | ![]() |
|---|---|---|
8 keysbest | 5 keys | |
12.7 cm | 17.37 cmbest | |
11.43 cmbest | 8.08 cm | |
6.6 cmbest | 5.23 cm | |
| ↓ lower better | 0.54 kgbest | 0.84 kg |
— | 46.56 mmbest |
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 with cover |
Installation & Mounting(1) | ||
Mounting Type | wall_mount | Over-the-knob |
Storage & Capacity(1) | ||
Key Capacity (keys) | 8 keys | 5 keys |
Design & Fit(3) | ||
External Height (cm) | 12.70 cm | 17.37 cm |
External Width (cm) | 11.43 cm | 8.08 cm |
External Depth (cm) | 6.60 cm | 5.23 cm |
Build & Design(2) | ||
Body Material | metal | Metal |
Product Weight (kg) | 0.54 kg | 0.84 kg |
Security & Access(1) | ||
Lock Type | pushbutton | Alpha/numeric combination |


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

Professional reviewers at CLKsupplies commend the KeyGuard SL-590 for its robust heavy-duty metal frame and impressive internal storage capacity, noting the effectiveness of the weather guard.
Everyday users and reviewers generally praise the product for its excellent storage capacity relative to its size and its durable construction that withstands outdoor elements.

Professional assessments highlight the product's ease of use and practicality for property management. However, a critical security review by the LockPickingLawyer revealed a significant vulnerability, demonstrating that the internal mechanism's simple sliding plate with notched rods can be decoded without tools.
Users generally provide positive feedback regarding the ease of use and practicality for property management. Common themes include appreciation for the straightforward operation in challenging conditions such as low light or when wearing gloves.
“you can see how much space is still in here”

“very easy to use”

“a good amount of keys”


