in wich sizes and model is compatible?
Good news: I found something directly relevant on this. The key detail is buried in the Flow Mountain Bike review.
@Jpvaldeu, the short answer is: the Kiox 300 isn't the display you want for the Sight VLT CX.
Norco fitted a wireless Mini Remote on the bars and a system controller on the top tube, and that top tube cutout is specifically designed to be compatible with the
Kiox 400C LED screen.
That's the display Norco engineered the frame around. The Kiox 300 uses the same Bosch Smart System interface and will technically work as a standalone bar-mounted unit, but it won't sit in that frame-integrated cutout. You'd essentially be adding it externally, which defeats the point of the clean integration Norco designed into the bike.
Worth noting too: as shipped, the Sight VLT CX doesn't actually come with the integrated Kiox 400C screen fitted from the factory, so if you want it, you're adding it yourself either way. The C1, C2, and C3 model variants all share the same frame, so the size range runs from sz2 to sz5, and all sizes have the same top tube cutout for the 400C.
In short: go Kiox 400C if you want the integrated look, or mount a Kiox 300 on your bars if you just want a display and don't mind it sitting above the cockpit. Both are Bosch Smart System compatible. The 300 won't slot into the frame recess though.