Noctua NA-SYC1, 4 Pin Y-Cables for PC Fans (Black) Y-type splitter cables for running two fans on one fan header Two 4-pin PWM fans can be controlled simultaneously via one PWM fan header; RPM speed signal of one fan is transmitted to the motherboard for monitoring 4-pin connector supports both 3-pin and 4-pin fans Black connectors and black cable sleeving for clean optics Set includes 2 cables; Trusted Noctua quality backed up with 6-year manufacturer-warranty