W-VHS was named so because "W" in Japanese sounds like "double" (Daburyū, ダブリュー) 
The recording medium of W-VHS is a ½-inch metallic magnetic tape stored in a cartridge the same size as VHS. The tape can be used to store 1035i (HD) or 480i (SD) and a double channel of 480i (for storing 3D programs)(SD2) analog signals (but not 480p, 720p or 1080i). The video signal is recorded using a method called "time compression integration" which "records separated component video, luminance and color signals are offset by time in alternating parts of the video track". Because video signals are recorded in component form instead of the color under method used by S-VHS, standard definition image quality for W-VHS is typically much higher, due to the lack of noise caused by a chroma sub-carrier. Audio is stored in the VHS Hi-Fi or S-VHS Digital Audio formats.
W-VHS VCRs were one of the only devices consumers could use to record a standard or high definition video signal via an analog Y/Pb/Pr component interface. Very few devices with this capability exist, possibly due to content copyright restrictions. W-VHS has also been used for medical imaging, professional previewing, and broadcasting.
Currently, it is very difficult to find either W-VHS VCRs or tapes. Since W-VHS tapes are harder to find users have turned to the similar Digital-S (D-9) tape. While D-9 tapes are still not that easy to find, they are more available than W-VHS tapes in certain regions. JVC Professional even recommends the use of them for W-VHS. The running time between W-VHS and Digital-S is not the same; a Digital-S tape with a length of 64 min is approximately 105 min when used with W-VHS.