600 Series Blow Molded. Blow Molded Folding Chairs by National Public Seating features contoured plastic seat and back, textured powder coated gray frame and cross braces. The cross braces in the textured powder coated frame serves to provide extra strength. The 600 series chairs are also easy to handle, light weight and stain resistant. They are perfect for both indoor and outdoor setup. The chairs can be easily folded or stacked atop another, making them portable.