Master Lock 4400D Bluetooth Padlock Review

The Master Lock 4400D Bluetooth Indoor Padlock was released to the public on January 4, 2016. Since then, the lock received mixed reviews from consumers, so our team decided to test it to see what everyone was talking about.

Master Lock, an American-based company that develops locks and safes, has several Master Lock Vault eLocks, including the 4400D and 4401DLH. Both of these locks are integrated with a Bluetooth 4.0 chipset and have a companion app, allowing them to connect with iOS and Android devices.


The 4400D durable construction consists of a wide metal body (1.9” H) and a 0.3-inch thick boron carbide shackle will provide maximum resistant to sawing and cutting. To eliminate tampering, the lock will automatically stop accepting keypad entries for 60 seconds and blink red after 3 consecutive unsuccessful attempts have been made. The lock utilizes FIPS approved and NIST recommended algorithms to prevent sniffing and tampering. A notification will also be transmitted to the app-enabled smartphone to warn the user of potential tampering activity.

Users can also share an unlimited amount of access with others on a temporary or permanent basis. To activate the lock, just create a free account in the Master Lock Vault eLocks app. After the account is created, verify it by inputting the included code into the app. The lock’s personal default directional combination is also included in the package, so users can access the lock without their app-enabled device.

On the front panel of the lock, there is a circular button that provides simple backup access, when the battery fails. This feature utilizes a directional code sequence that is very simple to achieve. To recharge the emergency battery temporarily, just remove the weather cover on the bottom of the lock and touch a high-quality alkaline 9v battery to the contacts. There is no specific way the battery needs to touch the connection points to gain enough power to unlock the lock. According to the company, the onboard CR2032 battery provides a run time of 4 months in “Swipe Unlock” mode and 2 years in “Touch Unlock” mode.

The “Touch Unlock” mode allows the user to open the lock, with a simple press of the center button, but the authorized smartphone will need to be within the Bluetooth range (10 t 15 feet). When the button is pressed, the lock will immediately turn blue and begin searching for nearby devices. Once the device is located, the lock will turn green and unlock at which time users will be able to hear an audible click

Once the lock is activated, users have 5 seconds to open the latch, before it automatically relocks itself. This time frame can be adjusted by accessing the Manage Lock menu in the app. The “Locker” mode offers more security, because it prevents the app-enabled device from communicating with lock.

The downside to the lock is its limited Bluetooth range. Bluetooth technology eliminates the need for a wireless connection, but instead requires the app to be within the Bluetooth range to activate the lock. However, users do not need to be within the range to send temporary combinations or alter guest access. To permit someone to utilize the app, each guest will need a Master Lock Vault account, which links from the owner’s primary account.


The Master Lock 4400D Indoor Bluetooth Padlock works flawlessly with a ZTE Axon 7. The app works as described and the ability to share access of the lock with others makes it even more worthy of its price tag.

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