10 could be much less expensive inversion of the strainer 10 would be accomplished by a user pushing on the second surface 19 of the strainer portion the annular flange 14 of the strainer 10 helps to secure the strainer 10 within a desired sink drain opening not shown by engaging a surface of the sink not shown the flange 14 preferably has a substantial width to provide such securement it should be understood however that some circumstances may not require the strainer 10 to have a flange of any width or may require only a very small flange width further the material of the flange 14 may be a flexible material similar to the strainer portion 12 or a rigid material similar to the preferred material of the post 16 the embodiment of fig1 shows a flange 14 comprised of a layer 22 of flexible or rigid plastic material and an outer ring 24 made of a suitable metal fig7 8 and 9 illustrate different embodiments of the invention fig7 shows an embodiment similar to fig1 except that the flange 14 is comprised of a solid metal ring 26 affixed to the upper edge of the strainer portion 12 by any known means fig8 shows the cross section of a strainer 10 having a flange 14 comprised of the same material as and integral to the strainer portion 12 fig8 as well as fig9 also illustrates the possible removal of the center post as it might be attached to the strainer portion 12 of the strainer 10 a tubular portion 30 of the rigid post member 16 fits within an opening 32 of the strainer portion 12 and is held in place by fastener 34 from the second surface 19 fig9.