The present invention regards a device designed for injection of fluids in a well bore, typically an offshore well bore for petroleum production and gas injection / gas lift system for fluid injection. The device comprises a outer hollow housing (1) with an internal body (3) moveable within the outer housing (1) which in a first closed position is closed with a metal to metal seal system between the outer housing (1) and the internal body (3), which internal body (3) is operated by pressure differential across the internal body (3). The internal movable body (3) is connected to the outer hollow housing (1) by means of a retainer key (6). The retainer key (6) comprises a shear arrangement and is arranged to keep the valve in a fixed closed position, where fluid pressure is to overcome the pretension of the retainer key (6) in order to open the device. When the device is shear opened, it can be kept in this open position as the retainer key (6) is locked to the outer hollow housing (1).