The very odd 3M Keypad Mouse

Product reviewed: 3M Keypad Mouse (Model LX451)

A combined mouse + numeric keypad in one device, intended for users who need cursor movement and number entry at the same time despite limited desk space. Introduced around 2004.

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Key features mentioned

• Two-button optical mouse with scroll wheel
• Built-in numeric keypad (includes keys like Enter, Equals, and Backspace)
• Retractable USB cable
• Includes travel bag
• A dot on the 5 key for touch-finding (to help locate numbers without looking)
• Labeled 3M model LX451 (made in China)
• Uses a USB composite device / two USB input devices when installed on Windows

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User experience & performance

As a mouse

Works correctly:

• Cursor movement functions normally
• Clicking, dragging, and scrolling work
• Installing drivers/software on Windows 7 succeeds

But usability is poor for extended use:

• The device must be pressed straight down to type on the keypad; when used as a mouse it falls off at a steep angle
• No palm support, making it potentially painful over time
• Ergonomics sacrificed due to the keypad/mouse combination

As a numeric keypad

Types numbers only with Num Lock ON:

• When Num Lock is OFF, the keypad acts like arrow keys plus Page Up/Down and Home/End
• With Num Lock ON, it correctly enters numbers

Major drawbacks:

• Sliding problem: when typing, you must push straight down; using it at an angle causes it to slide around
• Key size mismatch:
  • Compared to a normal mouse: keypad mouse is too wide
  • Compared to a normal keypad: keys are too small
• Stiff keys: rubber dome switches feel high activation force (snappy, but harder to press)
• Equals key is redundant: in calculator apps, Enter effectively serves as equals
• Backspace key is awkwardly placed: corner placement, not convenient

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Comparisons made

• Vs. a standard full-size mouse: keypad mouse is wider and therefore less comfortable.
• Vs. a compact laptop mouse: retractable cable design evokes laptop-style compact mice; key location marker exists, but switching between a full keyboard and this keypad is still distracting due to key-size differences.
• Vs. laptop pointing devices / future touchpads:
  • Historically, trackpoints/trackpads may have motivated interest in the keypad mouse
  • Later touchpads improved scrolling and reduced demand for dedicated keypad input
• Vs. built-in numeric keypads in modern laptops: more laptops added numeric keypads, making this device obsolete
• Mac/trackpad context:
  • Mac users typically don’t get built-in numeric keypads (except niche history), but are comfortable with trackpads—so demand for a combo device is lower.

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Pros (as stated)

• Works perfectly fine as a mouse (functionality-wise)
• Allows mouse movement + number input in one device
• Potential versatility when Num Lock is off (arrow/page/home/end), which could be useful in games
• Backspace could theoretically act as a browser back button in browsers that support it (though modern browsers mostly don’t)

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Cons (as stated)

• Not good as a keypad: sliding ergonomics, small keys, stiff/high-force switches, awkward Backspace placement
• Not good as a mouse: steep angle, lack of palm support, uncomfortable for long use
• Equals key redundancy
• Key-size disconcerting when switching between this and a normal keyboard
• Overall practicality is questioned; the product seems like a compromised concept

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Pricing / reception mentioned

• $89.99 in 2007
• Amazon user rating cited: 2.5 / 5 stars
• Video concludes it was largely unimpressive to users and a non-successful product, though the concept is credited for being inventive.

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Overall verdict / recommendation

Not recommended. The device may function, but the video strongly argues it’s poor ergonomically and awkward as both a mouse and a keypad, making it more of an interesting concept than a practical daily tool.

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Unique points by speaker

• Primary reviewer: all product critique, usability testing (Windows 7, Num Lock behavior), ergonomics/key feel issues, comparisons, and final verdict. (No other distinct speakers are indicated in the subtitles.)