KYDZSafe edges - Each and every one of our edges and corners are rounded to a minimum of a 1 inch radius, allowing children to play safely without getting hurt by sharp edges and corners. KYDZStrong construction - at Jonti-Craft, we employ dowel-pin construction. This technique is stronger than the dado joints used by other companies and prevents weakening at the joint, where most stress occurs and extends lifetime by 50%. KYDZTuff finish - It's an ultravoilet acrylic coating that's as tough as the finish on bowling lanes and is enviromentally friendly too! It's an ultra-durable finish that resists yellowing and extra-strong resistance for daily wear. Caster mounted for mobility Valve, cap, and activity cover included