Pennsylvania Statutes Title 43 P.S. Labor § 155. Minimum wages to be paid by contractor may be stipulated

The specifications upon which contracts are entered into by any county, city, borough, town, township, school district or poor district for the construction, alteration or repairs of any public work or improvement may, at the option of any such political subdivision, contain the minimum wage or wages which may be paid by the contractor or his subcontractors for the work performed by laborers and mechanics employed on such public work or improvement, and such laborers and mechanics shall in such cases be paid not less than such minimum wage or wages.