Jambs give elegance to the system you chose. Jambs can be internal or external.
They have both an aesthetic role, basically defining the window, and functional role to protect the wall.
They are available in different shades of marble imitation wood shades to match.
Due to the laminated exterior surfaces, they are resistant to moisture, high temperatures, scratches and are easy to maintain.
They are made of aluminum or PVC and have both protective role , protects the wall from the weather, but can also help to improve the appearance of the facade.