This FC fiber optic  connector is used for 3mm jacket. It is an epoxy style connector used in conjunction with a fiber optic polishing machine and curing oven. 
|     Physical Characteristics | 
|    Material   | 
  Nickel | 
|    Compatibility | 
   3mm jacket | 
|    Fiber Type | 
   Multimode | 
|     Connector | 
|    Connector | 
   FC | 
| Package Information | 
|    Package Quantity | 
   50 Connectors | 
|    Product Weight | 
   1 lbs [0.45kg] |