Best Master Lock Key Safes

TL;DR: The Master Lock 5400EC Black offers a weather‑resistant, 4‑digit resettable dial with a 1.5‑inch (38 mm) exterior depth and a lifetime warranty, all for $29.95.

The box’s most noticeable spec is its exterior size – 6.25 inches (158 mm) tall, 3.25 inches (83 mm) wide and 1.5 inches (38 mm) deep – giving it a roomy cavity while still fitting on a standard door knob. Its metal‑plastic body and vinyl‑coated shackle are rated weather‑resistant, so it can survive temperatures from –20 °F to 120 °F without freezing.

Compared with the other four key safes in this roundup, the 5400EC sits in the middle of the weight spectrum: it’s heavier than the 5406D (0.7 pounds) but lighter than the 5423EC (1.7 pounds). Its height of 6.25 inches also exceeds the 5406D’s 5.25 inches and the 5423EC’s 4.58 inches, giving it a larger external footprint than those models while still being more compact than the bulkier 5440EC and 5441EC units.

Users consistently award it 4.7/5 stars across 25,191 reviews, highlighting the ease of setting a custom 4‑digit combination and the durability of the weather‑proof cover. Professional reviewers note that the lock can endure 500+ open/close cycles without structural failure, but they also point out that the dial may start to feel stiff after a year of heavy use. The interior space – 1 inch (25 mm) deep, 1 inch high and 2‑13/32 inches (2.4 in) wide – is praised for holding standard house keys, though several owners mention it’s too tight for larger car remote fobs.

Technically, the lock holds up to five standard (2 inch) keys, features a mechanical dial that you can reset at any time, and offers both over‑the‑knob and wall‑mount installation options. The limited lifetime warranty adds confidence for long‑term outdoor placement.

Best for: Budget-conscious buyers seeking a reliable entry-level option — the Master Lock 5400EC Black offers Exterior Depth: 1.5 inches (38 mm)

Avoid if: You want the best value‑per‑dollar in its price range

TL;DR: The Master Lock 5406D offers a 0.7‑lb, weather‑protected, over‑the‑knob key box with a 1.5‑in depth and 5‑key capacity, delivering reliable security at a budget‑friendly price.

This lock box packs a 1.5 in (38 mm) external depth and a compact 5.25 in (133.35 mm) external height into a lightweight 0.7 lb (317.5 g) package. The durable metal body with a vinyl‑coated shackle houses an internal cavity that measures 0.5 in deep, 1 in high and 2.25 in wide, comfortably fitting up to five keys without jamming. A built‑in weather cover and a 4‑digit numeric combination that you can reset add everyday convenience.

Compared with its peers, the 5406D is lighter than the Master Lock 5400EC (1.0 lb) and the 5423EC (1.7 lb), and it sits lower on the height scale than the 5400EC’s 6.25 in exterior. Its external width of 2.75 in is slimmer than the 5400EC’s 3.25 in, making it easier to mount on narrower knobs. While the 5440EC and 5441EC command higher price tags, the 5406D delivers a solid feature set at a modest $24.99.

Reviewers consistently praise the large internal cavity for preventing keys from getting stuck, and they appreciate the simple 4‑digit code that can be set to any combination. Professional reviewers note the anti‑jamming cavity and the lifetime warranty as strong points for property managers and short‑term rental hosts. Users also like the weather‑proof cover when the box is placed on outdoor gates or fences.

Beyond the basics, the lock features a vinyl‑coated shackle with a 0.406 in (10.31 mm) diameter and a 1.406 in (36 mm) length, offering resistance to tampering. The resettable code lets you change the combination whenever needed, and the lifetime warranty underscores Master Lock’s confidence in the product’s durability.

Best for: Budget-conscious buyers seeking a reliable entry-level option — the Master Lock 5406D offers External Depth: 1.5 in (38 mm)

Avoid if: You need alphanumeric combinations, app‑based tracking, or a lock that fits unusually thick knobs

TL;DR: The Master Lock 5423EC is a 1.7‑pound, waterproof metal key safe with a push‑button keypad that holds up to five keys and lets you set a 12‑character combination for $32.92.

The standout feature is its push‑button alpha/numeric keypad, which accepts combinations up to 12 characters and can be reset at any time. Large buttons are designed for low‑light or gloved use, and the metal housing measures 4.58 inches high, 2.06 inches deep and 3.125 inches wide, giving it a solid feel without being overly bulky. Its waterproof cover and vinyl‑coated shackle add protection for outdoor installations, while the limited‑lifetime warranty backs the build quality.

Compared with the other four safes in this roundup, the 5423EC is heavier than the 5400EC (1.0 lb) and the 5406D (0.7 lb), but lighter than the premium 5441EC (over 2 lb). It’s shorter than the 5400EC’s 6.25‑inch height, yet taller than the 5406D’s 5.25‑inch profile. Its exterior depth of 2.06 inches exceeds the 1.5‑inch depth of both the 5400EC and 5406D, giving a deeper interior without expanding the footprint. The 5440EC’s overall dimensions are similar, though the 5423EC carries a bit more weight.

Professional reviewers highlight the box’s durability and the ease of setting a custom code, noting that the resettable keypad makes re‑keying straightforward. Users commonly praise the straightforward wall‑mount installation and the reliable access it provides for landlords or homeowners. The main complaints revolve around the fixed wall‑mount design, which limits flexibility, and the lack of a backlit keypad, making entry difficult in total darkness. Some users also mention occasional keypad sensitivity when exposed to extreme weather, despite the waterproof rating.

Best for: Homeowners, landlords, or small‑business owners who need a well‑reviewed, permanent wall‑mounted key storage solution that can hold up to five keys.

Avoid if: You need a portable or temporary key holder, or you require a backlit keypad for very low‑light environments.

TL;DR: The Master Lock 5441EC is a wall‑mounted smart lock box with military‑grade encryption, 30‑100 ft Bluetooth range, and weather‑resistant metal construction, but its $186.14 price and hefty 2.6 lb weight make it a premium choice.

This model’s standout spec is its Bluetooth reach of 30‑100 ft, letting you unlock the box from across a yard or driveway without stepping inside. At a solid 2.6 lb (1180 g) and a depth of 205.7 mm, it feels robust enough for outdoor use while still fitting a standard wall mount.

Compared with the other four lock boxes in this roundup, the 5441EC sits at the high‑end of both price and size. It’s notably heavier and bulkier than the portable 5406D and the slimmer 5400EC, and its wall‑mount design differs from the primarily free‑standing peers, positioning it as a more permanent, premium solution.

Reviewers consistently praise the military‑grade encryption and the convenience of sharing access codes via the Master Lock Vault app. At the same time, users flag occasional Bluetooth hiccups and note that the larger footprint makes it less suitable for tight spaces. Professional reviewers also highlight its tamper alerts and the ability to keep a numeric keypad backup for when phones run out of battery.

Beyond connectivity, the box holds up to five keys, supports a resettable code, and runs on a CR123A battery that comes included. Its weather‑resistant metal body is rated for operating temperatures down to –40 °C, so it can stay outdoors year‑round without corrosion concerns.

Best for: Those prioritizing quality and willing to pay for premium performance — the Master Lock 5441EC offers Master Carton Quantity: 12

Avoid if: Reliability and user satisfaction are your top concerns

TL;DR: The Master Lock 5440EC is a Bluetooth‑enabled, weather‑proof key box with a 4‑digit combo, 10 mm body thickness and a 0.5 kg molded body that holds up to five keys.

The standout spec is its 10 mm‑thick molded body with a vinyl‑coated shackle and a built‑in Bluetooth module that talks to the Master Lock Vault apps. It also sends tamper and low‑battery alerts, runs on a CR123A battery, and survives temperatures down to –40 °C. At 0.5 kg (1.1 lb) it feels solid yet portable, and the internal cavity (22 mm × 87 mm × 64 mm) comfortably fits several house or car keys.

Compared with the other four key safes in this roundup, the 5440EC sits on the premium end. It’s heavier than the 5406D (which weighs about 0.7 lb) but lighter than the 5423EC (around 1.7 lb). Its internal depth of 22 mm exceeds the 5406D’s 12.7 mm, and its internal height of 87 mm is larger than the 5406D’s 25 mm. Unlike the 5400EC and 5406D, the 5440EC adds Bluetooth connectivity and app‑based alerts, giving it more smart features than those purely mechanical models.

Users appreciate the portable over‑the‑knob mounting style, noting that it can be installed in seconds without drilling. Professional reviewers highlight the anti‑jamming internal cavity that keeps the lock turning smoothly even when packed with multiple keys. The most common trade‑off mentioned is the limited storage of five keys, which some renters find restrictive compared with larger wall‑mount options.

Best for: Those prioritizing quality and willing to pay for premium performance — the Master Lock 5440EC offers Master Carton Quantity: 4 units

Avoid if: You need advanced features or professional‑grade performance