Compatibility and Versatility: Compatible with PBF40 and PBF40-M, suitable for bullfrog/wellspring 30 Coreless 10-00282. Suitable for cold, warm, and hot water, and various pools, spas, hot springs, and home hot tubs. Superior Quality Filtration: High-density PET fabric for improved filtration efficiency. Advanced compact pleated design increases the filter area, efficiently filtering out impurities and harmful particles such as sediment, hair, leaves, and sand, ensuring a safe and clean leisure experience. Easy Installation: Wellspring 10-00282 bullfrog filter. Simple installation, no tools required. The larger bottom opening perfectly fits the groove of the spa mounting assembly.The narrow opening goes up, the wider goes down. Convenient Cleaning: Easily clean impurities on the filter pleats. Cleaning frequency depends on usage, typically providing several seasons of service. Replace the filter when fabric is stained or clogged. Dimensions: This Replacement Filter has an open hole 3 3/8 inches (3.375") on the top, 4 1/2 inches (4.5") open hole at the bottom, 6 1/4 inches (6.25") length, 7 4/5 inches(7.8’’) diameter.