B-R408ENX 399,000 BTUs Pro Series Pool and Spa Heater - Natural Gas - Salt Water - ASME Certified filter-width_null inches The optional sliding collar is

The optional sliding collar is item #23625-00

For 8 inch SWC strainers

This is a Generic Heater Bucket Gasket G-358 replacement with dimensions for Hayward Comfort Zone for GKT7401/402 heaters

WW8050114 O-Ring

B-R408ENX 399,000 BTUs Pro Series Pool and Spa Heater - Natural Gas - Salt Water - ASME Certified filter-width_null inches The optional sliding collar isThis Raypak B R408ENX Digital Pool and Spa Heater is 399,000 BTUs, fueled by natural gas, and is ASME certified with bronze headers and Cupro nickel tubes for maximum protection. These salt water friendly Professional Series heaters feature a stainless steel burner tray and a more precise microprocessor control. They are specifically designed for commercial and high end residential installations up to 2,000 feet. The Professional Series pool heaters