"MASTER,SET USED TO ACCOMODATE SET UP OF FIXTURE FOR MACHINING THE 9TH THU 12TH STAGE COMPRESSOR AIR SEAL REAR O.D. SNAP DIA;CONSISTS OF HARDENED STEEL RING WHICH WILL BE SECURED IN A FIXTURE WHICH CONSISTS OF A HYDRAULIC CHUCK AND A CLAMP/BACKUP PLATE; 1.000 IN WIDE X 15.840 IN DIA"