The D2S bulb type is specified for both the high beam and low beam headlight positions across all listed model years of the Infiniti QX60, covering the 2014-2019 range.
The D2S is a high-intensity discharge (HID) bulb, which operates by passing an electrical arc between two tungsten electrodes within a quartz glass capsule filled with xenon gas and metal halide salts.
The "S" designation in D2S indicates the bulb uses a metal shroud around the arc tube, which controls light distribution and reduces glare. This distinguishes it from the D2R variant, which is designed for projector-style reflector housings without a shroud.
D2S bulbs operate at a standard voltage of approximately 85 volts after ignition, requiring a ballast and igniter to produce the initial high-voltage pulse, typically around 23,000 volts, needed to start the arc.
Because the Infiniti QX60 (2014-2019) uses the same D2S bulb for both high and low beam functions, the headlight system relies on a projector lens mechanism with a movable shield to switch between beam patterns rather than separate bulbs for each function.
D2S bulbs are not interchangeable with D1S, D3S, or D4S types despite a similar physical form. D1S and D3S contain mercury and differ in igniter integration, while D4S operates at lower voltage and uses a mercury-free formulation, making cross-substitution technically incompatible without system modifications.
The consistent D2S specification across all six model years indicates no change in the headlight bulb fitment for the QX60 within the 2014-2019 production period.