Ontology is made of forging one-time compression materials forging forming ，used to control the pipeline and other equipments switched on and off of fluid，there are Ming bar type and non-rising stem type ，and There are manual and hydraulic.
Basic：
| Nominal Size | 1-13/16"～4 -1/16" |
| Working Pressure | 2000Psi～20000Psi |
| Material Class | AA～HH |
| Specification Level | PSL1～4 |
| Performance Level | PR1～2 |
| Working Medium | oil, gas, mud, water |
| End Connection | conform to API |
