I've got a pair of unused Prime Primavera carbon aero bars in 420mm. They were bought for a build that's been delayed, and now I've got round to it, I've decided I want 400mm width.
The bars have been fitted into a stem and levers/hoods attached, but I realised pretty quickly when I did that, they're too wide for me. They have never seen the road and are currently sitting in the original box. There is a tiny chip to the lacquer/finish next to the logo; I don't think you can tell from the photos.
As you can see, they have the classic 'aero' shape as well as ovalised drops and moulded holes/channels for Di2 and fully internal routing if that's your thing.
My preference would be a swap for some good quality carbon bars at 400mm, or failing that I'm happy to sell for £100 posted.