Apparatuses for restricting fluid flow through a well conduit comprise a housing having a longitudinal bore and a seat disposed within the bore. The seat has a first position when the apparatus is in the run-in position and a second position when the apparatus is in the set position. The seat comprises an arcuate member comprising a plurality of slits defining a plurality of segment members having a gap there-between. Each of the gaps are variable such that movement of segment members inwardly causes the gaps to be narrowed or closed off completely when a plug element is disposed into the bore and landed on the arcuate member to move the arcuate member from the first position to the second position, causing restriction of fluid flow through the bore and the well conduit.