1·High-temperature models have a fluororubber seal and high-temperature grease, for extreme conditions where lower speeds are required.
高温模式有氟橡胶密封和高温润滑脂，在极端条件下较低速度是必需的。
2·Foreign Fluororubber more than 50 varieties, but only over 10 domestic species.
国外氟橡胶有50多个品种，而国内目前只有10多个品种。