(a) Subject to the provisions of subsection (b) hereof, any claimant who has performed labor or furnished material in the prosecution of the work provided for in any contract for which a payment bond has been given pursuant to the provisions of subsection (a) of section 3 of this act¹ or for which other financial security has been given pursuant to subsection (a) of section 3.1 of this act², and who has not been paid in full therefor before the expiration of ninety days after the day on which such claimant performed the last of such labor or furnished the last of such materials for which he claims payments, may bring an action on such payment bond or other financial security in his own name, in assumpsit, to recover any amount due him for such labor or material, and may prosecute such action to final judgment and have execution on the judgment.

(b) Any claimant who has a direct contractual relationship with any subcontractor of the prime contractor who gave such payment bond or other financial security but has no contractual relationship, express or implied, with such prime contractor may bring an action on the payment bond or other financial security only if he has given written notice to such contractor within ninety days from the date on which the claimant performed the last of the labor or furnished the last of the materials for which he claims payment, stating with substantial accuracy the amount claimed and the name of the person for whom the work was performed or to whom the material was furnished.

Notice shall be served by registered or certified mail, postage prepaid, in an envelope addressed to such contractor at any place where his office is regularly maintained for the transaction of business or served in any manner in which legal process may be served in the manner now or hereafter provided by law for the service of a summons, except that such service need not be made by a public officer.