This is a genuine Vernet wax thermostatic element for all Sirrus Gummers (Bristan brands) thermostatic cartridges which use the SK740012 element. The SK740012 fits into a wide number of Sirrus thermostatic cartridges.We are the official spares partners to Vernet for the UK: This thermostat element is a genuine Vernet element.The element measures 44mm in total length, with the metal element part 7.40mm in diameter. The circular part in the middle measures 14.7mm in diameter.If you need any help in identifying which element you need, please contact us.We deliver this thermostatic element worldwide.The SK740012 is used in and will fit thermostatic cartridges in the following Sirrus (by Gummers) shower valve mixers: - Sirrus Opac TS1503 Shower Mixer (110) - Sirrus Thermostatic Cartridge Thermostat SK1500-2 - Sirrus Stratus TS1850 and the TS1850 Dual Shower Valve (30) - Sirrus Stratus 1850 - Sirrus Thermostic Cartridge SK1850-2 Sirrus 1850-968 - Sirrus Calvus TS1600 Valve (SK1600-2 Thermostatic Cartridge) (10) - Sirrus Calvus TS1625 (SK1600-2 Thermostatic Cartridge) - Sirrus Duette BSM3000 - Sirrus Opac TS1500 (20) - Sirrus Assy Thermostatic Cartridge SKBQ1503-973C - Sirrus GOLD 1500 Antique Cartridge SK1500-7GP - Sirrus Stratus TS1875 - Sirrus 1500 Chrome Antique Cartridge Sk1500-7Cp - Sirrus TS1700 Thermostatic SK1700-2 (10) - Sirrus Ts750 Cartridge SK750-2 - Sirrus Ts6000 Cartridge SK6000-2Brand: VernetSpare Part: Thermostat ElementSK740012 is the result of the innovation of a wax thermostatic capsule throughout its inception since the mid-1930s. It can be used with a number of Sirrus / Gummers shower mixers stated above.Thermostat capsules, like the SK740012 regulate water temperature by mixing hot and cold water together to yield a water temperature suitable for a good shower. A mix of two temperature opposites by 50/50 will produce a moderately warm 38℃ or 100.4℉.Fun Fact: How Wax Thermostatic Elements Came to BeIn the year 1934, an application was filed with the United States Patent Office entitled “Thermostat”. The application was made by inventor Sergius Vernet. His invention works through the use of a wax motor principle which eventually made its way into the plumbing and heating industries.Sergius Vernet, the creator of the wax thermostat element was born in Bronx County, New York in 1899, the transition period between the Gilded Age and the aftermath of World War 1. He went on to reside in Yellow Springs, Greene County, Ohio. Vernet’s career as an inventor started when he was 19. Among the first of his patent application was originally filed in 1925 for a radiator shutter used in automotive engines. When he was 35 years of age, he patented the first-ever wax thermostat element which also initially designed for the automobile industry as a cooling agent. Around this time, the inventor established a small laboratory that eventually grew to become Vernay Laboratories. It is now known simply as flow control solutions provider, Vernay.The wax thermostatic element by Vernet was modified to be used for plumbing and heating. In 1970 and 1971, the capsule element found its way into the plumbing industry in Sweden and Switzerland respectively. Since then, it became a fundamental part of shower mixers granting a temperature output of shower or bath tap water in accordance with a shower user’s own preference. Vernet succumbed to a sudden heart attack in 1968, at the age of 69.The SK740012 Thermostat Element is eligible for next day delivery, provided it is ordered before 3:00 PM from Monday to Friday.