Euro H4s appear similar to H5s from the outside, though each uses different style bulbs. At first glance, they look a bit like H1s, as well, though these utilize two different reflectors behind each lens.
This is a pic of an H4 or H5 light on a Carrera.
And for the US DOT style sealed beam, this is what they look like as installed.
In sealed beams, the bulb is integrated into the reflector and lens unit and cannot be changed. The assembly can be replaced with H4 style lights that have the lens/reflector separate from the bulb, which can be changed out when required.
Sealed beams typically give relatively poor illumination, while the H4 replacements are usually E-code lights and are often much better. They use the same H4 bulbs as the Euro lights.