A pressure indicator including: a body including: a substantially cylindrical bore having a longitudinal axis; and a shoulder; a piston disposed at least partially in the bore, the piston including: a base; and a stem that extends from the base along the longitudinal axis; wherein the piston is located at a first axial position relative to the body when pressure of fluid acting on the base is below a threshold pressure; a first biasing element disposed between the base of the piston and the shoulder of the body, wherein a force of the first biasing element is overcome by pressure of fluid acting on the base at or above the threshold pressure, thereby allowing the piston to move to a second axial position relative to the body; a rotatable disc configured to rotate about the longitudinal axis, wherein the disc has a first rotational position when the piston is in the first axial position; and a second biasing element configured to urge the disc toward a second rotational position when the piston is in the second axial position characterized in that: the stem includes: a first groove aligned substantially parallel to the longitudinal axis; and a second groove aligned substantially orthogonal to the longitudinal axis and connected to the first groove; and the rotatable disk includes: a tab that is receivable in the first groove when the piston is in the first axial position; and wherein the tab is receivable in the second groove when the piston is in the second axial position. a body including: a substantially cylindrical bore having a longitudinal axis; and a shoulder; a substantially cylindrical bore having a longitudinal axis; and a shoulder; a piston disposed at least partially in the bore, the piston including: a base; and a stem that extends from the base along the longitudinal axis; wherein the piston is located at a first axial position relative to the body when pressure of fluid acting on the base is below a threshold pressure; a base; and a stem that extends from the base along the longitudinal axis; wherein the piston is located at a first axial position relative to the body when pressure of fluid acting on the base is below a threshold pressure; a first biasing element disposed between the base of the piston and the shoulder of the body, wherein a force of the first biasing element is overcome by pressure of fluid acting on the base at or above the threshold pressure, thereby allowing the piston to move to a second axial position relative to the body; a rotatable disc configured to rotate about the longitudinal axis, wherein the disc has a first rotational position when the piston is in the first axial position; and a second biasing element configured to urge the disc toward a second rotational position when the piston is in the second axial position characterized in that: the stem includes: a first groove aligned substantially parallel to the longitudinal axis; and a second groove aligned substantially orthogonal to the longitudinal axis and connected to the first groove; and the rotatable disk includes: a tab that is receivable in the first groove when the piston is in the first axial position; and wherein the tab is receivable in the second groove when the piston is in the second axial position. the stem includes: a first groove aligned substantially parallel to the longitudinal axis; and a second groove aligned substantially orthogonal to the longitudinal axis and connected to the first groove; and a first groove aligned substantially parallel to the longitudinal axis; and a second groove aligned substantially orthogonal to the longitudinal axis and connected to the first groove; and the rotatable disk includes: a tab that is receivable in the first groove when the piston is in the first axial position; and wherein the tab is receivable in the second groove when the piston is in the second axial position. a tab that is receivable in the first groove when the piston is in the first axial position; and wherein the tab is receivable in the second groove when the piston is in the second axial position.