The Jackel-DJ-545 front introduced in the mid-1970 's and it is by far the world 's most favorite sump check valve with over 10 million installed ! . The features Jackel 's ain 1-1/4 '' or 1-1/2 '' combination adapters and the most long-lived check valve flapper in the industry. This is of the world 's most time-tested sump pump check valves.