Whenever the sump is being sealed due to concerns about radon gas or odors we recomend installing model F-S2 right in the cover.
The sump model F-S2 Drajer is designed to be used as a part of the cover for a basement sump. Dranjer F-S2 seals permit unrestricted flow of water into sump pits while sealing out the entry of mold spores, insects and radon gas from the sump pit.
The "F series" can be used in homes where sub-slab suction has been included or may be considered in the future as a radon mitigation technique