Apple Pro Speakers were introduced with the Power Mac G4 (Digital Audio) and later shipped with the iMac G4. These speakers required a Mac with a built-in amplifier and a proprietary audio jack to connect.
Apple described these speakers as “designed by Harman/Kardon,” once a high-end audio company now owned by Samsung. Harman/Kardon also designed the popular iSub subwoofer and SoundSticks in partnership with Apple that were released in 2000. In both the Apple Pro Speakers and SoundSticks, Apple contributed the industrial design and mechanical engineering, while Harman/Kardon manufactured the audio components of the product.
The Macintosh PowerBook Video Cable allowed PowerBook 100-series laptops to be connected to Apple monitors sold in the early 1990s. Both ends of the cable were Apple-proprietary.
This cable allowed users of the earliest PowerBook series, such as the PowerBook 160 with a grayscale-only display, to plug into a color Apple monitor and use the PowerBook with a color screen.
According to an Apple Support document, the cable supported a resolution of 832×624 and was compatible with the following laptops: PowerBook 1400-series, PowerBook 190-series, PowerBook 520-series, PowerBook 5300-series, PowerBook 540-series, PowerBook 550c [Japan Only], PowerBook 160/165/180, and PowerBook 165c/180c.