Description
The Logitech K400 Plus, model 920-007119, is a compact wireless keyboard with a touchpad built into the right hand side of the deck, aimed at controlling a computer connected to a television from across a room. It has been on sale since August 22, 2015, carries a 4.4 star average across 37,852 ratings, and is ranked 2nd in Computer Keyboards in the captured listing data. That is one of the highest category positions of any product in this catalog.
Logitech publishes an 84 key layout, a 3.5 inch touchpad, a 2.4GHz Unifying receiver with a 33 foot range, up to 18 months of battery life with a stated usage assumption, an on and off switch, a spill resistant design, and a weight of 13.8 ounces across dimensions of 13.95 by 5.5 by 0.93 inches.
Who this is for
This is a living room keyboard. The single design decision that defines it is putting the pointing device on the keyboard itself, which means you can operate a computer from a sofa with the whole thing balanced on your lap and no surface for a mouse. Logitech’s own framing, controlling a PC connected to a television, is exactly right, and the 33 foot range is a real specification here rather than a padded number, because the distance between a sofa and a media PC is the use case.
It is not a keyboard for typing at a desk all day. The compact 84 key layout means the number pad is gone and several keys are doubled up on function layers, and the touchpad is a poor substitute for a mouse in any work that involves precision. Anyone who wants a full layout with a separate mouse should look at the Logitech MK345 keyboard and mouse set instead.
The compatibility list has a significant omission
Logitech names Windows 7, Windows 8, Windows 10 and later, Android 7 or later, and Chrome OS. macOS and iOS are not on that list, and neither is Linux. That absence is easy to miss because the compatible devices field says “Laptop, PC, Smart TV, Tablet, Smartphone” without naming platforms. If your media machine is a Mac, this listing does not claim to support it, and we will not claim it on Logitech’s behalf.
The connection, and the port it takes
This is not a Bluetooth keyboard. It uses a 2.4GHz radio link through Logitech’s Unifying receiver, which plugs into a USB-A port. Unifying is a named technology rather than a generic dongle, and its advantage is that one receiver can carry several compatible Logitech devices, so a keyboard and a mouse can share a single USB port.
The practical trade is the same as any receiver-based device. It occupies a USB-A port permanently, which is a problem on machines that have only USB-C, and the receiver is a small item to lose. Against that, a 2.4GHz link works during startup and in firmware menus where Bluetooth often does not, which matters on a media PC you may need to configure before an operating system has loaded.
Logitech Options software is named for adjusting controls and saving preferences, which means some of the customization depends on installing an application. The listing does not say which functions require it.
Battery: 18 months, and the condition is actually stated
This is one of the better battery disclosures in this catalog, because the footnote is present rather than implied. Logitech quotes up to 18 months and then states the assumption: “Assumes up to two hours typing per day. Actual battery life will vary with use, settings and environmental conditions.” That is precisely the kind of condition most listings omit, and it lets you scale the number to your own use.
There is also a physical on and off switch, described as helping the battery last longer. On a device that lives on a sofa and gets sat on, a hardware switch is worth more than a sleep mode.
Two specification fields undermine the picture. “Battery Type = 18 months” is not a battery type; the runtime figure has been copied into the wrong field. And “Batteries = 1 Lithium Polymer batteries required” describes a rechargeable cell, which does not match an 18 month replaceable-battery design with a power switch. The listing never states which batteries the keyboard actually takes, how many, or whether they are included, and we are flagging that rather than guessing.
The touchpad, the keys and a field that contradicts the listing
The touchpad is described as 3.5 inches, and a separate line gives dimensions of 2.99 inches high by 1.85 inches wide, which is consistent with a 3.5 inch diagonal. Those dimensions appear inside the bullet recommending an upgrade to a different model, so it is not entirely clear which product they describe, but they match the stated size.
The keys are described as comfortable and quiet, and the chassis as spill resistant. The spill resistance carries a footnote marker with no rating, no volume of liquid and no test standard attached, so treat it as a design intent rather than a specification. There is no IP code of any kind.
One field is directly contradicted by the listing’s own copy. “Keyboard backlighting color support = Single Color” implies the keys are illuminated. The upgrade bullet in the same listing recommends the Logitech K830 “for increased comfort, illuminated keys, USB/Bluetooth connectivity and a rechargeable battery,” which only makes sense if this keyboard has none of those things. The backlighting field is wrong, and this keyboard is not backlit. That matters more than usual on a living room keyboard, since the room is often dark.
Two smaller oddities: “Number of Processors = 1” is inherited from a computer listing, and the product title reads “Black PLUS Floral” while the color field says Black, so check the variant you are ordering.
What is published that most listings omit
Logitech states a product carbon footprint of 4.9 kg CO2e and describes the product as certified carbon neutral. Whatever weight you give that, it is a specific and checkable disclosure of a kind that almost no accessory listing includes, and the same brand publishes a comparable figure on the Logitech M185 mouse in this catalog.
Not published: battery size and count, key travel, key switch type, whether the touchpad supports multi-finger gestures, whether the function row requires a modifier key, or the receiver’s compatibility with specific other Logitech devices. For a keyboard, the absence of any key travel or switch information is the notable gap.
Other wireless accessories in this part of the catalog include the Logitech M720 Triathlon mouse and the Nelko P21 label maker, and the full selection sits in this section of the catalog.
Who should buy it
Buy the K400 Plus if you want one device to control a media PC from a sofa, you value a stated battery condition and a hardware power switch, and you have a USB-A port to spare. Skip it if you use a Mac, since the listing does not claim macOS support, if you need backlit keys in a dark room, since despite one specification field this keyboard is not backlit, or if you need a full size layout and a real mouse for daily work.
