This is a  special 60-degree template:
you can easily cut triangle, half triange, and diamond from pre-cut stripes.
The numbers in the template indicate that how wide strip you need to cut.
1 1/2", 2 1/2", 3 1/2"and 4 1/2" wide strips you can customize the template.
The seam allowance is included in the template, which is 1/4".