Not saying yours are knock offs but plenty going around these days, just check out this:
Terms and Conditions
From Defi:
Recently, package-copied products and counterfeit products which our trademarks (Defi logo and others) and address are put in are sold in the marketplace around the world.
And we receive inquiries from people who purchased those by mistake.
Those counterfeit products infringes our intellectual property rights.
Please be careful enough because those may disadvantage a person who purchases those.
Please note that we, Defi, do NOT accept liabilities when the following troubles occur:
When those replicas are purchased by mistake.
When Defi products or vehicles break down by installing those replicas.
Sample pictures of replica
LEFT: replica package / Right: real Defi package
LEFT picture: package replica / RIGHT picture: real Defi gauge
LEFT: replica / RIGHT: real Defi gauge
Knock offs do the same dial dance when they start up etc and look exactly the same, the only way to see the difference of the actual readings from knock off to real would be have them tested.
The only major differ is they dont need the control unit to work just like the Defi Racer gauges.
My mrs cousin has actually sent me a set as a gift so will see if I can get them tested and post results but very hesitant about using them.
Will make a nice addition to a GT console racing wheel for Gran Turismo etc kekeke.
***A vendor on SAU is selling these aswell and people have no complaints.