EK Quantum PC-O11D XL D5 PWM D-RGB User Manual page 2

Before you start using this product please follow these basic guidelines:
Please carefully read the manual before beginning with the
installation process!
The EK Fittings require only a small amount of force to screw
them firmly in place since the liquid seal is ensured by the
rubber O-ring gaskets.
The use of corrosion inhibiting coolants is always recommended
for any liquid cooling system. EKWB recommends any of the
EKCryofuel for worry-free usage.