nominal size

1 x 1 Inch
1"
1-1/2 x 1-1/2"
1-1/2"
1-1/4"
1/2 Inch
1/2 x 1/2 Inch
1/2"
2"
3"
3/4 Inch
3/4 x 3/4 Inch
3/4"
4"