Spiker has a spinner pin Agitator that chews up Materials making clogging dust but pattern is adjustable. A friend of mine that has a spyker hopper on a ground logic says can't fill hopper all the way with seed because it doesn't flow right. Also he gets false starts since Materials coated in control products tend Not to start flowing right away when gate plate is opened. Lesco push Spreaders are the same way with flow isues but more gentle on materals. When you put a breakthru Agitator in a Lesco Spreader or Permagreen it fixes flow isues and All types of Materials start flowing instantly when holes are opened. Few guys buying new Lesco push Spreaders are buying Breakthru Agitators at the same time I heard from a rep at Site one.