Koolance video bridge connectors link multiple video water blocks together with ease. Flow can be directed in series or parallel. CNT-VDB4 is for combining three (dual L-bracket) video blocks which are in consecutive PCI-Express slots. This product is only compatible with Koolance VID-series water blocks which have detachable fitting bases (launched in 2013 or later). NOTE: Hose barbs are recommended for 10mm (3/8in) and 13mm (1/2in) ID tubing sizes to avoid conflicting with the water block or video card. Koolance's product warranty does not cover the use of 3rd-party coolants, coolant additives, or corrosion. Koolance LIQ-702 or LIQ-705 coolants are strongly recommended to help avoid issues with mixed metals or biological growth. Additionally, do not use aluminum with bare (unplated) copper or bare (unplated) brass in the same system. Do not use silver with nickel in the same system.