There is an excellent after market sieve manufactured by loewen. It has replaceable louvers, and each wire hole has a plastic insert so that neither the hole or wire will wear out prematurely, and if it does happen, you can easily replace the wire or the louvers. Another great feature on them is that they have indexible, spring loaded adjuster handles, which keeps the sieve opening exactly where you put it at all times, plus they move smoothly and easily, something you can't say for IHC sieves, which at times you have to get a long pipe out to get the thing to move. They also manufacture an exterior chaffer and sieve adjuster, which mounts on the outside of your combine, which allows you to adjust your chaffer or sieve from the outside, and if you have chaff throwers which make it difficult to get your adjusters, this is a great feature.