Dont waste your money

Purchased and used for two days with iPhone and Apple Watch app. Rarely ever recognized the knock on the phone and the Apple Watch app was slower than me typing my password in about 3 seconds. Also, had instances where I was not able to access Mac desktop because the app was trying to knock and kept repeating my password over and over again without logging in. Bottom line, save yourself five bucks, wait until its free. This is just a novelty with no actual functionality or necessity.

vballer15 about Knock – unlock your Mac without a password using your iPhone and Apple Watch