This is one of many, many headgear shops. The population of Saigon (yes, even many of the natives still refer to Ho Chi Minh City as Saigon) is rapidly approaching 9 million people and their main transportation is the scooter and most wear helmets. Talk about a niche market!
Fortunately, there are separate lanes for scooters in the city. Even so, crossing the street is perhaps the most adventurous, adrenaline producing sport one can do here.