Parker Davis markets StepStake sign holders that provide the maximum economy for an attractive, durable, and easy to use outdoor sign installation when used with a 4mm corrugated plastic sign board. The company’s nursery marker stakes are fabricated of durable 9 gauge galvanized steel. The cards are 4 mm corrugated polypropylene and will hold up for several years outdoors. The 7-inch W x 5.5-inch H and 2.5-inch W x 6-inch H cards are available in eight colors.