I had these fitted a couple of years ago, there are numerous models.
https://www.summitracing.com/int/par...ec66/overview/
They are ok but I have lost a couple of butterfly valves and they didn't sell the butterfly valve separately, I'm not sure whether that's changed. The electronic controller supplied is a bit 'flaky', that's probably why they've changed the model and gone to a wireless system.
Mine's not exactly the sort of thing you're after as I have a y junction in each branch of the exhaust system and it can be opened behind fake side pipes.
cheers