U.S. Seal Shaft Seal [PS 1903] [5 8" Shaft] [Silicon Carbide] (PS 1903) guangdong Replacement bulbs are useful because Replacement bulbs are useful because UV based sanitation systems depend on a functioning lamp to continue delivering the treatment support they were designed to provide or no longer provides the illumination needed for nighttime use and visual appeal Seal PS 1903 shaft seal is made for compatible 5 8 inch shaft applications where a silicon carbide seal is the better long term answer but it is often the part that determines whether the job feels finished or whether the pump comes back with fresh leakage around the seal plate area