input: from typing import List
  
  def find_integer_difference(arr1: List[int], arr2: List[int]) -> int:
      """
      Given two arrays of equal size, arr1 and arr2.
  
      Each element in arr1 has been increased (or decreased in the case of negative) by a specific integer, which is denoted by the variable x.
  
      Consequently, arr1 transforms into arr2. Two arrays are considered identical when they have the same integer elements appearing with the same frequency.
  
      Return the integer x.
  
      Examples:
      >>> arr1 = [2,6,4], arr2 = [9,7,5]
      3
      >>> arr1 = [10], arr2 = [5]
      -5
      >>> arr1 = [1,1,1,1], arr2 = [1,1,1,1]
      0
  
      Constraints:
      1 <= arr1.length == arr2.length <= 100
      0 <= arr1[i], arr2[i] <= 1000
      The test cases are designed such that there is an integer x making arr1 equal to arr2 by adding x to each element in arr1.
      """
output:     # Assuming both arrays are already sorted and have the same elements frequency-wise
      if not arr1 or not arr2 or len(arr1) != len(arr2):
          return 0  # According to the problem constraints this situation should not happen
      
      # x can be found by subtracting the first element of arr1 from the first element of arr2
      x = arr2[0] - arr1[0]
      
      return x