Features: 1) Working principle: under the circumstance of lowest below -40oC, electrothermal thread will heat 30 seconds after electrifying oil, then start-up 30 seconds after frame throwing, can attain the service lifetime to 2,000 times 2) Working and usage request: a) Not leak the oil under cold pressure 1MPa b) Not leak the oil under hot pressure 0.1MPa c) Screw thread connected: according to requirements 3) Outer: nickel-plated/steel #35