 The body is cylindrical with a concave conical depression, instead of a dome-shaped lens at the tip, to cause wider distribution of light.All miniature bulbs, including some LED sets, have a wedge base, though their designs are inconsistent with one another, making it somewhat difficult for the average consumer to change bulbs.To replace a bulb, the plastic base of the bulb must usually be changed by straightening the two wires and pulling the glass part out.