With some types of beads and marking materials, optimal bead application is difficult to achieve. Bead coatings are available that assist applicators in achieving proper bead embedment depths. Because Type III beads are more difficult to properly embed than Type II beads, Type III beads are coated with an adhesion or floatation coating prior to application. Type II beads are usually not coated. Adhesion coating is inspected according to Test Method . Check with the glass bead manufacturer or TxDOT Materials Laboratory for current bead coating information.