A New Spreader Aftermarket Auger # 75615 kit. You get Auger D6075, Auger Cap D6191, and 5/16 x 3/8" Set Screw D6140.
This is used by Western, Fisher and SnowEx on various salt spreaders.
Western uses it on the Low-Pro 300W.
Fisher uses it on the Quick-Caster 300W.
SnowEx uses it on the 575X, the 1075X, the 575V, the SR-210, the SP-125, SP-225 and the SP-325 in addition to the -1 newer versions of these spreaders.
Curtis also uses it on some of the smaller tailgate spreaders.
Meyer 10.75 EZ-flow spreader part # 37213
For a break down of related parts, check this link.