These are most suited for large face outdoor signs where either the size or windage and flexing of the face may be an issue, or signs mounted in high locations, or signs that are not required to have content changed often such as for branding. Can be either single or double-sided, they are usually made with an aluminium frame with a special springloaded aluminium extrusion for the body to hold the flexi-face tightly in place. Fluorescent lighting is normally used in these because of their large size, however LED's are becoming more frequently used as installation costs continue to become cheaper, and the annual running and maintenance cost being significantly reduced. The printed flexi-face material can be usually expected to last for 10 years.