Aperture, output and mounting hardware decide this, not preference.
Retrofitting is cheapest when the lamp matches the existing hole. A trailer cut for 4 inch round lamps stays on 4 inch round lamps unless there is a reason to re-panel.
The 4 inch family runs from 7 diodes to 40, including a strobe version. The oval family runs from 10 to 24 diodes with low-high and flashing on the 16LED model. For a plain high-output tail signal the ovals are the simpler choice.
The slimmest oval is 20 mm deep. Round lamps with grommets sit deeper once the grommet is included — the F3 Piranha lamps measure 1.8 inches deep with the grommet fitted.
If corroded lead joints are your recurring failure, the 22LED oval with its sealed 3-pin connector addresses that directly; in the round family the Piranha lamps fit a 3-pin right-angle plug.
4 inch grommet-mount round lamp, SMD 2535 7 LED
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4 inch 7 LED round lamp with reflective bezel
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4 inch round 9 LED lamp for higher rear output
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4 inch round 40 LED lamp with low-high and strobe
View product →The 4 inch round family, in the 40LED lamp and the F3 Piranha 12 LED strobe version.
The 190*86*20 mm oval at 20 mm deep.
Send the panel aperture, voltage and function. We will shortlist models and quote your quantity.