This is an exclusive, patented textured backing developed by Scotch 3M for its magnetic audio tapes.
Key Features of the Posi-Trak Backing
Delamination Protection: The matte textured backing reduces the risk of the magnetic oxide layer peeling off onto the back of the next tape layer during winding.
Smoother Winding: It provided improved friction and grip, allowing the tape to wind tightly and evenly without slipping or "pulling," preventing edge damage.
Stable Tracking: The backing minimized static buildup and ensured flawless tape movement past the tape heads, significantly reducing head clogging and flutter in both types of tape recorders.