RVL-001
The original model of the Wii system (RVL-001) is the first revision of the Wii released. It comes in two colors, white is the original color, and black was released later in the Wii's lifespan (2010).
Features
DVD playback
There is zero way to visually tell the difference between a Wii supporting DVD playback vs a Wii with a new drive, only supporting Wii Optical Discs and GameCube discs, apart from black color Wiis, which almost always have a Wii Optical Disc and GameCube disc drive.
boot1 signing bug
RVL-001s can have a boot1 that has the signing bug unpatched, thereby allowing software such as BootMii to be installed to boot2.
GameCube backwards compatibility
The RVL-001 comes with a disc drive able to read GameCube discs, 4 GameCube controller ports, and 2 memory card slots. The Wii uses BC to load MIOS, the special IOS for GameCube mode.
boot2 version
Almost all up to date RVL-001s have boot2v4 installed. Certain late models may have boot2v5 installed, but boot2v5 RVL-001s cannot be confirmed, apart from certain new models sold in the UAE.