Flameless Ration Heater

A U.S. soldier uses a flameless ration heater. Flameless ration heater

Zesto-Therm’s Flameless Ration Heater (FRH) is a patented water-activated and environmentally friendly heater. It is especially designed for the U.S. Army to heat a soldier’s individual eight ounce Meals, Ready to Eat (MRE) field ration – like the Milspec MRE.

Since 1990, Zesto-Therm has made over 100 million Flameless Ration Heaters.

An FRH heats food without the need for fire – safely and quickly. FRH food heaters are used easily in situations where fire is prohibited or not recommended. The FRH is ideal for soldiers in the fields, campers, hunters, boaters or anyone interested in emergency preparedness.

An FRH MRE heater is small (measuring 5 1/2 inches long x 4 1/2 inches wide and about 3/8 inch thick), and weighs about one and a half ounces.

Zesto-Therm FRH MRE heaters are easy to store and have a five year shelf life.

Spent pads are easily disposed, with no toxic materials. The FRHs are made from powdered food grade iron, magnesium, and sodium.

Each FRH is individually packaged in a sturdy, leak- proof polybag which serves as the heating container for the MRE. The polybag measures 5 3/4 inches wide by 14 1/4 inches long.

Simply cut open the top of the FRH polybag sleeve, Place the MRE food portion inside the bag next to the heater. Add plain water to the “Fill Line”, and fold the open end of the bag.

In just 12 minutes – enjoy a hot meal anytime, anyplace.


  1. Vapors released by activated heater contain hydrogen, a flammable gas. Do not place an open flame in the vapor.
  2. Vapors released by activated heater can displace oxygen.
  3. Hot water leakage can burn and cause a cold- weather injury.
  4. After heating, the heater bag and MRE pouch will be very hot. Use caution when removing MRE pouch from bag.
  5. Discard heater and bag after use. Do not drink the water remaining in the bag or use it in food items.



Operating Instructions

1. Remove MRE pouch from carton and save carton. 2. Tear off top of bag. Place MRE pouch in bag with heater. 3. While holding MRE pouch and heater above lines on bag, pour water into bag until it reaches a level between lines. Slide heater and MRE to bottom of bag, and fold top of bag to side opposite heater.
FRH Operating Instructions 1 FRH Operating Instructions 2
4. With heater underneath MRE, hold bag level for a minute to let heater soak up water. 5. Stuff assembly into carton with top of bag folded over top of MRE and heater underneath.

6. Prevent water from escaping while your ration warms.

FRH Operating Instructions 3 FRH Operating Instructions 4 FRH Operating Instructions 5


To prevent water from escaping and to maximize heat output, always keep:

  • BAG folded OVER TOP of MRE; and

After ten to fifteen minutes (depending on air temperature) top half of bag can be torn off and the MRE can be removed and eaten.

Knead MRE to ensure uniform temperature. CAUTION: The contents will be hot.


Heating Instructions for Frozen MREs

  1. Use two heaters: one to thaw, one to heat.
  2. To thaw frozen MRE: Follow instructions above except, add water to bag before adding MRE. When heater begins to feel warm, add MRE to bag.
  3. To heat thawed MRE: Follow instructions above.
  4. In cold weather, heater can be placed in BDU pocket to heat MRE. Make sure folded end of bag is up to prevent water from leaking out.