I am using a 15ft cable for AppleTV 4k (2nd gen) and Vizio P65-F1. It works great. Just to note that I did experience signal drops when using the Vizio's HDMI 1 input, but I've found that this happens with another brand's 6ft cable as well. It turns out that the problem is related to Vizio's input 1. Input 3 works fine.