This document is a tender document from ONGC for the job of "Re-tubing of heat exchangers E-112D, E-512B and E-2503 A/B of LPG 1, 2 & CFU Plant at Uran". It includes an invitation to bid, details about the tender such as cost of documents, earnest money deposit required, qualification criteria, and addresses for submitting bids. It also includes indexes of instructions to bidders and general contract conditions that would apply to the job. In summary, this tender document outlines all the key details for a bid for re-tubing heat exchangers at an ONGC plant in Uran, India.