Model Number: YHT010-1-A Brand Name: Galaxy and Yinhe Key Specifications/Special Features: Incorporated in all standard manhole covers, and available separately with rain cap2-inch high flow pressure and vacuum vent valve provides breathing for petroleum product tankersAerodynamic porting facilitates extremely high throughputMandatory roll over seal off, as required by UK health and safety executive includedFeature has proven effectiveness many times in tanker rollover accident where it has protected lives, prevented dangerous and costly spillage and prevented pollution