VertEdge can also be used with 18mm & 25mm foam shock pads. VertEdge allows the shock pads to move independently of the artificial grass if they expand, as the perimeter grass is fixed to the VertEdge and not the Shock pads. Foam Shock pads are unstable and can expand from the heat of the sun, which causes wrinkles and creases in the artificial lawn when the grass is fixed direct to the shock pad. VertEdge eliminates this potential problem as there is space in the VertEdge cavity for the shock pad to expand into. As the artificial lawn is adhered to the top edge of the VertEdge and tucked down, and not adhered directly to the Shock pad, there is no risk of the shock pad causing wrinkles or creases in the lawn if there is any expansion/movement within the shock pads. Using VertEdge with foam shock pads, also creates a stronger, safer and more natural appearance to the artificial lawn.