Darrell - the H242SL bagger definitely will NOT fit on your Husqvarna RZ4219 zero turn mower. This bagger will only fit on Husqvarna tractors with a 42" deck. We would need to know the 9-digit model number of your mower in order to determine the proper bagger. A 2007 or older model uses a different bagger than the 2008 and newer models.