Reynolds 531 has now been largely replaced in new frames by still-better steels. The latest, for race or sports frames, is Reynolds 953.[3] Reynolds worked closely with Carpenter Speciality Alloys to develop 953. It started reaching frame builders in 2005.[4] 953 is based on a specially developed maraging steel stainless steel alloy that can achieve a tensile strength in excess of 2000 MPa (853 is around 1400 MPa), giving a good strength-to-weight ratio. Because of the high strength of the steel, extremely thin tube walls (down to 0.3 mm) can be used, thus reducing the weight.[5] ~wiki