The string grader is designed to separate smaller from bigger size produce. In a string grader produce rolls over the strings to the outfeed. Undersized produce falls between the strings.

The string grader has various applications like undersize removal or as a pregrader for onion toppers. By separating smaller from bigger produce, the capacity per individual onion topper increases. Pregrading also increases the quality of the topping process.
The String grader has 17 strings of 70 cm long which can be adjusted between 50-75 mm. The diameter of the strings is 25 mm. The size adjustment of strings can be manual or automatic.