The Mercury Mystique dome light requires bulb size 211-2 or 6411 depending on the specific version. Data for the bulb sizes covers the range from 1995 to 2000.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercury Mystique uses the 211-2 bulb for its dome light across the full 1995-2000 model year range.
The 211-2 is a festoon-type bulb with an SV8.5 base, a 41mm length, and a 12V, 12W rating, conforming to ANSI standards applicable in the US and Canada.
The front dome light on the 1996-2000 Mystique takes the 6411 bulb, which is also a festoon type with an SV8.5 base but has a shorter 36mm length and a lower 5W draw compared to the 211-2.
Both the 211-2 and the 6411 share the same SV8.5 base type, though their differing lengths make them non-interchangeable in practice despite the shared base.
The rear dome light on the 1996-2000 Mystique uses the 12961, a Philips part number designation rather than an ANSI standard number.
The 12961 is a T10 miniature wedge bulb with a W2.1x9.5d base, operating at 12V and 5W, and its wedge base design is physically distinct from the SV8.5 festoon base used by the 211-2 and 6411.
Because the 12961 uses a wedge base and the 6411 uses a festoon base, the two 5W rear and front dome light bulbs are not interchangeable with each other despite sharing the same wattage and voltage ratings.