I know EXACTLY what they are and YOU DON'T NEED THEM. You are implying they are a "must have." Perhaps you could explain "why this is"
a cheap junk (or even bought new) tail/ stop socket and lamp does many things at very little money. The lamp puts a load on wiring which can show up bad connections that a simple volt /ohm test might not, and they can be used to protect circuits when hunting a short. I used to use them in series with a battery charger on small bike batteries. The uses are many. You can configure the assembly for higher or lower current draw And, LOL, it has a "built in" spare stop/ turn/ park / tail lamp................
