The V-belt is a V-belt with a V-shaped cross-section,
the V-belt's trapezoidal shape gives it good non-slip contact with the pulleys, due to the mechanical principle of wedging (it must not be tensioned, otherwise abnormal rapid wear will occur).
Li is the measurement taken on the inside;
Lw or Lp is the measurement taken at the primitive.
Le or La is the measurement taken outside.
AVX belts are toothed belts: these notches make it possible to support pulley diameters smaller than normal, which is generally the case with variable speed drives.