Cartridge, Check Valve, to fit A-dec® Century Plus® Control Block; Pkg of 3 Blue base with duckbill Package of 3 (A-dec® #38.0518.00) A-dec® and Century Plus® are a registered trademark of A-dec, Inc. DCI has no affiliation with A-dec and A-dec has not authorized DCI replacement parts to be used on or in connection with A-dec® products.