Martensitic and duplex stainless steel tubing are commonly used for oil and gas applications containing CO2. Completion equipment manufacturing requires use of solid round bar or heavy wall hollows. Material properties for this stock are not identical in all cases. Material properties as well as corrosion characteristics are discussed for 13Cr, 13Cr - 5Ni - 2Mo and 25Cr alloys. Corrosion testing of modified or Enhanced 13Cr solid bar stock, UNS S41425 and other compositions in H2S - Cl- and pH is reported in coupled and uncoupled condition. Corrosion testing of various super duplex bar stock at various H2S - chlorides and temperature in CO2 environment is reported. Impact value requirements, welding issues and special consideration required for these alloys for completion equipment is discussed. Modified 13Cr and Super Duplex Oil Country Tubular Goods (OCTG) are readily available, however, availability of completion equipment raw material compatible with these OCTG is limited. Keywords: Martensitic, 410 Stainless Steel, 420 Modified Stainless Steel, 13Cr, Super 13Cr, Modified 13Cr, Super Duplex, Stress Corrosion Cracking, Hydrogen Sulfide, Carbon Dioxide, Chlorides, PH.