vw t4 parts needed

Hi all,
Can anyone help please im after the rear small rear roof vent on the top on the van as mines brittle,

It is for a VWT4 petrol autosleeper 1994  high top.

Or will any others fit,
I would be grateful for any help advice on where to get one.

Thanks Phill

When we had the Duetto I replaced the smaller roof vent in the washroom and I believe it was a standard size. Mine came from Magnum Motorhomes local to me but there will be other suppliers on line. I was advised to purchase sealant at the same time.