Vacuum hoses

Can anyone tell me the internal diameter of the vacuum hoses, as I am looking to replace these (whilst fitting a catch tank). By the way am I right in thinking that the internal diameter of the breather pipes is 10mm and 8mm? Thanks in advance.

I bought 2 metres of 3mm and 2 metres of 4mm - ended up using some from each! the rest went into my “stock” pile for another day.