The present invention provides a pressure alarm for use in conjunction with conventional pressure gauge unit systems, as a replacement pressure gauge and alarm, or as a pressure alarm system. The invention provides adaptable alarm feedback signals for an operator, preventing the unexpected loss of pressure when using a gas cylinder, pressure boiler, or other device. The invention provides an alarm that may be a visual, audible, electronic, or mechanical low-pressure alarm and may include a means of ordering replacement supplies or sending a warning message. A system controller and memory module prevents false alarms and eases the burden of the operator while allowing external input and control.