Compatible with Sundance Spas hot tub water cleaner systems 2012 and later, including J-200, J-300, J-400, and J-LX series. Also compatible with part numbers: 6472-841, 6472-857, 3LRK, 94-1552, UVL-3LRK-1. Package includes 2 bulbs. For optimal performance, it is recommended to replace the bulb annually to help reduce maintenance costs. Easy to install: Simply remove the screws, enclosure cover, and gasket, then slide the replacement bulb into the quartz tube. Backward compatible with older models. Color may vary slightly due to lighting and screen display differences; this does not affect functionality. Color: As shown Material: Glass Package Contents: 2 x Pool and Spa Bulbs Note: Only the items listed are included. Note: Light reflection and display differences may cause slight color variation from the actual product. Measurement may vary by +/- 1-3 cm.