18 the opposing surfaces of magnets 24 and 27 are of the same polarity so that they repel each other as they get closer together the same can be said for magnets 22 and 27 as they approach each other when the flapper 16 goes toward the open position of fig2 the end tab 28 is used to allow the magnets 24 and 27 to be away from the specially machined complementary surfaces that engage when the flapper 16 engages the seat 14 it is cheaper to do it this way than to drill blind bores in the flapper and seat sealing surfaces although to do so can be an alternative way to use the magnets 24 and 27 to provide a dampening of the velocity and the resulting momentum force as the flapper 16 goes to the closed position of fig3 as shown in fig3 magnet 24 is on a longer radius from pivot 18 than magnet 27 which still allows taking advantage of like poles repelling each other the orientation can also be changed to position magnet 27 on the same arc as magnet 24 to create the dampening effect of magnets repelling each other however the offset orientation.