Bleeding brakes - tubing size

[GT Driver]

I've searched online but to no avail - can anyone advise what inside diameter size clear / transparent hosing I need to fit snugly over the Brembo bleed nipples?

 

I was going to buy some tubing from a hardware store but they come in sizes 5/8 inch, 3/8 inch and 1/2 inch. I am guessing 3/8 but wondering if it's still too big.

 

Thanks

[Richf]

http://www.ebay.co.uk/itm/one-man-use-brake-and-clutch-bleeding-tool-vizibleed-universal-/121926602167?hash=item1c63644db7:g:BekAAOSwoudW6ZNg

 

I've usually just used one of these