If the numbers didn't give it away, the Sleekbook 14 will be a 14-inch model, while the Sleekbook 15 will have a 15.6-inch display. The smaller model will be powered by AMD's latest Trinity processors, whereas you'll find Intel Core series chips stuffed inside its bigger brother. As the Sleekbook name suggests, they're designed to be particularly slender, although don't offer enough power under the hood to qualify as.
HP says they'll both pack high-definition displays (probably 1,366x768 pixels, rather than full 1080p) as well as up to 1TB of storage. There's no word yet about how much RAM is on board or how fast the processors are, so we'll have to wait and see how they perform. They're available in black or red and, like much of HP's recent range, feature the Beats Audio logo -- hopefully the built-in speakers will be slightly better than the usual rubbish.
The Envy M4, meanwhile, is a 14-inch machine (also offering a high-definition resolution) packing in the latest Intelprocessors inside its slim, brushed metal jacket. It's somewhat more expensive than the Sleekbooks so I'm expecting Intel Core i5 or i7 options with hopefully up to 8GB of RAM. There's no separate graphics card on board though, so don't expect it to tackle much in the way of gaming.
All three models are due to launch on 26 October -- the same launch date as Windows 8 -- so it's unsurprising that all three will come with Microsoft's new software on board. While having the latest operating system might initially seem exciting,, rather than the standard keyboard and trackpad, so having no touch option in the screen might not offer the best experience.
Hybrid devices -- powerful tablets designed with keyboard docks -- offer a great combination of touch input and physical keyboard typing, and I reckon it's these devices that .
Still, they're pretty new concepts and generally don't come cheap, so it's inevitable that Windows 8 will be still be most commonly found on standard laptops for at least the next couple of years.
HP's new additions are hardly breaking any boundaries, but with slender designs and starting prices of $500 (£310) and $560 (£350) for the Sleekbook 14 and 15 respectively and $900 (£555) for the M4, they might be an affordable entrance into Windows 8 if you're not fussed about having truckloads of power. Bear in mind though that those prices will rise significantly with VAT once they cross the Atlantic.
All three are due to launch in the US on 26 October with hopefully a UK launch to follow soon after, although nothing has yet been confirmed.
What do you think to HP's new kit? Are low prices and portability important to you or would you rather have a specced out monster in your hands? Let me know in the comments below or over on our Facebook page.