The Raypak R335A/R335B Indoor Stack Kit is a Raypak heater venting component intended for the model family identified in the product name. Venting parts such as drafthoods, stack kits, and stack assemblies are not generic accessories; they must be matched to the heater model, installation location, fuel/exhaust requirements, and applicable local codes. This part is typically used when replacing a damaged vent component, converting or completing an installation, or restoring the correct indoor vent configuration for the heater. Confirm model compatibility and part number 006698 before ordering or installation. Raypak heater venting component for the listed model family Used for indoor or outdoor vent configuration as specified in the product title Important for maintaining the correct heater exhaust path Confirm heater model and local code requirements before installation Use part number 006698 when matching the replacement component