This two piece set comes together with an inner and outer presser foot.  These feet are used for any unison feed or compound feed walking foot machine.  This includes the TN-650BL, TN-750BL, TN-1541, TN1508 and 1510 flat bed machines as well as the TN-246A and TN-1341 machines.  They come in various sizes from 1/8, 3/16, 1/4, 5/16, 3/8 and 1/2"