two subs are held in a fixed position relative to each other when assembled to a string and run into a wellbore . a reservoir of fluid is defined in a wall between the subs . the reservoir has one or more outlets connected by a short jumper line to an adjacent tool to be operated . at the appropriate time , set down weight breaks a shear pin to reduce the reservoir volume and create pressure in the exit lines . the exit lines can be connected to operating pistons in adjacent tools to actuate them or to perform other desired functions using a stream of pressurized fluid . the device can be set for one time or multiple cycles where fluid in the reservoir can be replenished and re - pressurized for multiple cycles of operation .