General Service Lamps are the most common filament lamps. They range in size from the 15 watt A-15 to the 1500 watt PS-52. These lamps are designed for 120, 125, and 130 volt circuits in the USA and in 220-240V in Europe and all are equipped with screw bases but with B22 in the United Kingdom.

The larger wattages are manufactured in either clear or inside frosted bulbs, while the 200 watt and smaller bulbs are usually frosted.

High wattage lamps are used primarily in commercial and industrial applications. So-called Soft White lamps are popular in homes because they achieve maximum light diffusion from the filament without glare or harsh shadows.