I found this on Amazon today to use with my backpack sprayer. The kit has a high volume and low volume spray nozzle for your sprayer. I'm ordering it today:
https://www.amazon.com/Smith-Performance-Sprayers-182620-Adjustable/dp/B01N7LXGEH/ref=sr_1_4?keywords=field+king+sprayer+parts&qid=1666032462&qu=eyJxc2MiOiI0LjQ4IiwicXNhIjoiMy43OCIsInFzcCI6IjMuMzAifQ%3D%3D&sr=8-4