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, and UVL-3LRK-1. Backward compatible with older models. Package includes 2 pool and spa 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. Color: As shown. Material: Glass. Package contents: 2 x Pool and Spa Bulbs. Note: Only the items listed are included. Light reflection and display differences may cause slight variations in color compared to the actual product. Measurement may vary by +/- 1-3 cm.