A pressure indicating device, comprising: a housing including: a barrel having an internal surface defining a cylindrical bore therein, within the housing, a first portion that is permeable to visible light, a first end member having an internal portion defining a first fluid channel therethrough, a second end member positioned opposite to the first end member along a longitudinal axis of the cylindrical bore, the barrel disposed between the first and second end members, a first interface between the barrel and the first end member and forming a fluid-tight seal therebetween, and a second interface between the barrel and the second end member and forming a fluid-tight seal therebetween; a piston movably disposed within the cylindrical bore, a first variable volume defined by the internal surface, the piston, and the first end member of the housing; a second variable volume defined by the internal surface, the piston, and the second end member of the housing, such that the second variable volume is sealed between the piston and the second end member of the housing; an inlet port defined by the first end member of the housing and in fluid communication with the first variable volume; a piston bypass tube defining a bypass channel disposed outside the cylindrical bore and in fluid communication with the inlet port; an outlet port defined by the second end member of the housing, the outlet port in fluid communication with the piston bypass channel; the pressure indicating device characterized in that, the piston is configured to move within the cylindrical bore and be located along the longitudinal axis of the cylindrical bore according to only a fluid pressure in the first variable volume and a fluid pressure in the second variable volume, the piston being biased toward the first end member by a charge of gas stored within the second variable volume having a pressure greater than atmospheric pressure; and wherein displacement of the piston within the cylindrical bore in a direction toward the second end member performs work on the gas disposed within the second variable volume, thereby imparting a reaction force against the pressure force imparted onto the piston by the pressure in the first variable volume. a housing including: a barrel having an internal surface defining a cylindrical bore therein, within the housing, a first portion that is permeable to visible light, a first end member having an internal portion defining a first fluid channel therethrough, a second end member positioned opposite to the first end member along a longitudinal axis of the cylindrical bore, the barrel disposed between the first and second end members, a first interface between the barrel and the first end member and forming a fluid-tight seal therebetween, and a second interface between the barrel and the second end member and forming a fluid-tight seal therebetween; a barrel having an internal surface defining a cylindrical bore therein, within the housing, a first portion that is permeable to visible light, a first end member having an internal portion defining a first fluid channel therethrough, a second end member positioned opposite to the first end member along a longitudinal axis of the cylindrical bore, the barrel disposed between the first and second end members, a first interface between the barrel and the first end member and forming a fluid-tight seal therebetween, and a second interface between the barrel and the second end member and forming a fluid-tight seal therebetween; a piston movably disposed within the cylindrical bore, a first variable volume defined by the internal surface, the piston, and the first end member of the housing; a second variable volume defined by the internal surface, the piston, and the second end member of the housing, such that the second variable volume is sealed between the piston and the second end member of the housing; an inlet port defined by the first end member of the housing and in fluid communication with the first variable volume; a piston bypass tube defining a bypass channel disposed outside the cylindrical bore and in fluid communication with the inlet port; an outlet port defined by the second end member of the housing, the outlet port in fluid communication with the piston bypass channel; the pressure indicating device characterized in that, the piston is configured to move within the cylindrical bore and be located along the longitudinal axis of the cylindrical bore according to only a fluid pressure in the first variable volume and a fluid pressure in the second variable volume, the piston being biased toward the first end member by a charge of gas stored within the second variable volume having a pressure greater than atmospheric pressure; and wherein displacement of the piston within the cylindrical bore in a direction toward the second end member performs work on the gas disposed within the second variable volume, thereby imparting a reaction force against the pressure force imparted onto the piston by the pressure in the first variable volume.