6mm barbed fitting made from nickel coated brass with O-ring seal for 8mm PVC, PU, PA, silicone or PE hoses with an inner diameter of 7-9mm. G1/4" outer thread. height 35,5mm, fitting inner diameter 6,6mm.

Note for watercooling beginners:
The connectors for hoses(7/16", 3/8",1/2") are provided with measurements in mm in our shop. These can differ by +-1mm, which is no problem as hose clamps have to be used for installation. If the hose is to be mounted without a clamp, a larger fitting should be chosen. With some fittings that tend to be larger, it is possible though that a hose with an inner diameter of 13mm actually does seal without a hose clamp.
 

Overview:
10mm (3/8") hose clamp: up to 8mm none, from 10mm up required
10mm (7/16") hose clamp: up to 8mm none, from 10mm up required
12mm (1/2") hose clamp: up to 11mm none, from 12mm up required
13mm (1/2") hose clamp: up to 11mm none, from 13mm up required