For loop through specific Worksheets

[mason0567]

I need to create a for loop to cycle through Worksheets 2-6 to run an if statement on each individual one and take action on that specific sheet matches those conditions. This is what I have currently:

Dim i As Long
Dim j As Long
If CheckBox1.Value = True Then
    For i = 3 To 373
        For j = 2 To 6
            If Sheet(j).Cells(8, i).Value = "CriteriaString1" Then
                Sheet(j).Cells(8, i).EntireColumn.Hidden = False
            End If
        Next j
    Next i
Else
    For i = 3 To 373
        For j = 2 To 6
            If Sheet(j).Cells(8, i).Value = "CriteriaString1" Then
                Sheet(j).Cells(8, i).EntireColumn.Hidden = True
            End If
        Next j
    Next i
End If