13mm barb fitting made from nickel coated brass with O-ring seal for PVC, PU, PA, silicone or PE hoses with an inner diameter of 11-13mm. G3/8" outer thread. The hose must be fixated with a zip tie or hose clamp. Inner diameter of fitting: 10mm.

Note for watercooling beginners:
The connectors for imperial hoses(7/16", 3/8", ½") 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