It is recommend to fill with counter pressure to ensure CO2 stays in solution. This can be monitored on the gauge and adjusted using the blue 8mm ball valve. 

This Talos A-Type Filling coupler is fitted with a 9.5mm duotight x 5/8" Female fitting. Suitable hosing to fill would be KL06248 EVABarrier 6.3mm(1/4inch)ID x 9.5mm (3/8inch)OD (12m)

The liquid filling side can be interchanged with:
8mm duotight x 5/8" (included in the coupler by default)

This coupler is required to fill Talos A-Type Kegs. It can be adapted to suit many different filling systems.