The Quilting pins are designe to secure the insulation inside the blanket in its place. It is important that the insulation inside the blanket doesn't settle down or slide around inside and create openings in the insulating envelope created by the removable and reusable blanket.

The washers are self locking purpose into the quilting pins, after the quilting pins are installed into the insulation covers or insulation blankets, use a self locking washer to lock the quilting pins to fasten.