The rocker assembly with a bearing block ensures that your hopping foot and needle bar work in tandem to create beautiful stitches. This custom-milled part is has been meticulously designed for APQS machines. Your rocker assembly should provide many years of service before showing wear signs. Excess up and down play in your hopping foot is a sign that the rocker assembly should be evaluated. This item is only for machines that were built prior to 1/1/2019.