This is the User’s Manual for the AppleColor Monitor 100 digital XRGB video monitor from Apple. The ACM100 was designed to be used with the ///, or an Apple IIe with an adapter card.
Initially, Apple sold an XRGB monitor made by Electrohome, Ltd., to go with the Apple ///. Later, Apple licensed the internals and manufactured their own shell to match the design of the ///. Electrohome was an electronics and appliance company that also supplied monitors and parts to various arcade cabinet manufacturers. A company history can be found here.
Here is a photo of the Electrohome monitor that Apple sold. (External link to Bill Degnan’s page.)
Please note that the ACM100 is not the same as the AppleColor High Resolution Monitor, seen here.