Collection: SV8.5 Bulbs

The SV8.5 base: the technical designation for the festoon bulb

SV8.5 is the technical designation of the base:

• S = symmetrical base (both ends are identical)
• V = shape of the metal contact
• 8.5 = diameter of the contact in millimeters

This designation is primarily used in technical catalogs and industrial standards. Commercially, you will more often find the designations C5W (electrical) or Festoon (French commercial).

SV8.5 = C5W = Festoon: three names, one product

All three designations refer to the same physical bulb: an elongated glass cylinder with two metal contacts at the ends, a format suitable for rectangular automotive dome light housings.

Which designation to use? No preference — all bulbs sold under one of these three names are compatible with each other. On the packaging of quality bulbs, you will often find all three mentions together ("Festoon C5W SV8.5") to avoid any ambiguity.

Choosing the right length

Size is the discriminating factor — always check the housing length before purchasing. The three standard formats:

• SV8.5 31 mm — city cars, small dome lights
• SV8.5 36 mm — versatile size, the most common
• SV8.5 42 mm — large dome lights, minivans, SUVs

To identify your need, remove the old bulb and measure its total length from one contact to the other.

SV8.5 variants

Several bulbs share the SV8.5 base depending on the wattage:

• SV8.5 5W (= C5W) — the most widespread, standard dome lights
• SV8.5 10W (= C10W) — more powerful, for large dome lights or spacious trunks
• SV8.5 LED — LED versions in all lengths, in white and colors

LED allows all these versions to be replaced by a single product with very low consumption and long lifespan — ideal for heavily used vehicles (taxis, VTC, converted vans).