Just took delivery of my new Mocal Boost Gauge but Im a little confused by the vacuum connector

it has a 1/8 BSP female connector on but I need an adaptor to enable me to fit my standard vacuum hose onto - cant for the life of me remember what size the hose is though - think its about 3mm

Anyway I see theres a fitting kit available but at £10 or so its more than i want to pay and more than i need as i alreayd have a gauge fitted.

Heres the kit u can get showing the adaptor i need

Can anyone point me in the right direction of the adaptor i need

I had a look on ebay but cant seem to find the right one

Failing that ill just have to have a look locally