The real thing, and, has never let me down for 2 straight decades. There are a lot of wannabe fake ones that "look" like they are blocking stuff this one misses but that's not true, they are just "stealing" those stats by stepping in front and blocking them before it can by moving itself up in the page handler queue. Don't be tricked by fakes or moofed by reviews of novices/kiddos who can't configure their devices properly.