Modultra Waterboy (WOBO) : Worlds smallest Nvidia 4090 FE water block. Designed to be ultra thin at a just under .530 inch ( 13.5mm ) thick from the back of the PCB. This card excels in small form factor builds, especially sandwich style builds where a radiator can be placed over the GPU slot. The Waterboy block is CNC machined from brass, copper, stainless steel and acetal. WOBO is finished in Cerakote ceramic coating for superiority durability and corrosion resistance.This WOBO is G1/4 port.WOBO uses the stock rear spring from the Nvidia 4090FE and installation is not possible without this spring.Condition: New (never used)