Most modern airlines have moved away from strict "minimum weight" requirements, as these have been replaced by more practical functional and safety standards. Instead of a number on a scale, airlines focus on "proportionality" and the ability to perform safety duties. A flight attendant must be able to sit in a standard jumpseat and fasten the harness without the need for an extension, and they must be able to pass through emergency exits (which are often narrow) and move easily down the aisle. Some airlines still maintain a Body Mass Index (BMI) guideline—usually requiring a BMI between 18 and 25—but this is increasingly rare in Western markets due to labor laws. The most common physical requirements today are height-based (to reach overhead bins) and "reach" tests (usually around 210cm). However, in certain regions, such as parts of Asia and the Middle East, more traditional and rigid grooming and weight standards are still practiced as part of the airline's brand image.