to close abruptly unless the motor 50 continues to operate to provide the necessary force in the direction indicated by the arrow 26 so as to hold the door or hatch open to prevent this from occurring it may be desirable to provide a fluid material in the fluid area 43 one fluid which may be used is a gas such as nitrogen collectively working with the piston 41 the fluid can provide a counterbalancing force to aid in both the opening of the door or hatch and the maintaining of the door or hatch in the open position as shown in fig1 this counterbalancing is achieved using the pressure and volume principles at work upon the fluid in fluid area 43 as the piston 41 is moved in the direction indicated by arrow 26 the fluid is forced through orifice 40 in the direction indicated by arrow 36 when the piston reaches full extension as shown in fig5 it is no longer being driven by the motor 50 at this point the piston 41 will naturally tend to move in the direction indicated by arrow 26 and return to the closed position as shown in fig4 this tendency is opposed by the dampening effect created as the return of the fluid to area 60 is resisted by the flow of the fluid from a high pressure area 60 to a low pressure area 43 fig7 through orifice 40 while the invention.