Hair gel used in o brother where art thou?

While the exact brand of hair gel used in *O Brother, Where Art Thou?* is not publicly known, it's safe to assume that the styling product used on George Clooney's character, Ulysses Everett McGill, was a common, readily available hair gel of the time.

Here's why:

* Period accuracy: The film is set in the 1930s, and while there were specialized hair products available, they were not as ubiquitous as they are today.

* "Slicked-back" style: The character's hairstyle is a classic slicked-back look that could be achieved with any strong-hold hair gel.

Considering the common hair products of the era, it's likely that a pomade or a petroleum-based gel were used to create the iconic look. These types of products were popular in the 1930s for their ability to create strong hold and shine.

While the exact brand remains a mystery, the film's production team likely chose a product that would accurately reflect the time period and help achieve the desired look for the character.