our company develop the HP refillable cartridge .Be suitable forHP8230/HP8238/HP8250.
To use in HP Cartridge:NO.HP02/NO.HP801/NO.HP177(C8721/C8771/C8772/C8773/C8774/C8775.)
The cartridge have only Refill hole, no vent hole, charge the ink from refill hole. Plug rubber in the refill hole when use it.