4k Video Downloader Key is a software for downloading YouTube videos and subtitles which are of high quality. The speed of the download will be determined as per how fast your connection and internet connection. A faster internet connection will mean faster download speed. The 4K video downloader key is the best suitable tool for people who just started using computers because the application will not require settings and it will start working soon after installation.4k Video Downloader Key is a software for downloading YouTube videos and subtitles which are of high quality. The speed of the download will be determined as per how fast your connection and internet connection. A faster internet connection will mean faster download speed. The 4K video downloader key is the best suitable tool for people who just started using computers because the application will not require settings and it will start working soon after installation.