the corrosion resistance without the use of precious metals. Monel was used for much of the exposed metal used in the interior of the Bryn Athyn Cathedral in Pennsylvania, religious seat of the General Church of the New Jerusalem. This included large decorative screens, doorknobs, etc. Monel also has been used as roofing material in buildings such as the original Pennsylvania Station in New York City. The 1991–1996 Acura (Honda) NSX came with a key made of Monel. Oilfield applications include using Monel drill collars. Instruments which measure the Earth's magnetic field to obtain a direction are placed in a non-magnetic collar which isolates them from the magnetic pull of drilling tools located above and below the non-magnetic collars. Monel is now rarely used, usually replaced by non-magnetic stainless steels. Monel is also used as a protective binding material on the outside of western style stirrups. Monel is used by Arrow Fastener Co., Inc. for rustproof T50 staples. Monel has also been used in Kelvinator refrigerators. Monel was used in the Baby Alice Thumb Guard, a 1930s-era anti-thumb-sucking device. Monel is used in motion picture film processing. Monel staple splices are ideal for resisting corrosion from use in continuous-run photochemical tanks. Alloys Monel is often traded under the ISO standards 6208 (plate, sheet and strip) 9723 (bars) 9724 (wire) 9725 (forgings) and the DIN 17751 (pipes and tubes). Monel 400 Monel 400 shows high strength and excellent corrosion resistance in a range of acidic and alkaline environments and is especially suitable for reducing conditions. It also has good ductility and thermal conductivity. Monel 400 typically finds application in marine engineering, chemical and hydrocarbon processing, heat exchangers, valves, and pumps. It is covered by the following standards: BS 3075, 3076 NA 13, DTD 204B and ASTM B164. Large use of Monel 400 is made in alkylation units, namely in the reacting section in contact with concentrated hydrofluoric acid. Monel 401 This alloy is designed for use in specialized electric and electronic applications. Alloy 401 is readily autogenously welded by the gas-tungsten-arc process. Resistance welding is a very satisfactory method for joining the material. It also exhibits good brazing characteristics. It is covered by standard UNS N04401. Monel 404 Monel 404 alloy is used primarily in specialized electrical and electronic applications. The composition of Monel 404 is carefully adjusted to provide a very low Curie temperature, low permeability, and good brazing characteristics.