When labeling electrical wires and terminal strips, go with the 3M ScotchCode SPB Pre-Printed Book. This book gives you 60 labels with pre-printed numbers and symbols for all your marking needs. Each marker label is made of a vinyl-impregnated cloth film with a top coat and natural rubber adhesive. They perform well in temperatures ranging from 32 to 150 degrees F (0 to 66 degrees C).