Military rations, also known as combat rations or survival rations, are prepared and packaged meals specifically designed to meet the nutritional needs of service members in combat situations or adverse conditions. There are several types of military rations used by different armed forces around the world. Here are some examples:

1. Individual combat rations (ICR): These are the most common rations and are designed to provide a complete meal for a soldier during a day of combat. They typically include a variety of packaged foods, such as canned meat, fish or chicken, energy bars, cookies, dried fruits, candy, instant drinks, and condiments.
2. Improved combat rations (RCM): These rations are similar to RCI, but often include additional and more varied options. They may contain more elaborate main dishes, such as pasta, rice or stew, as well as a greater selection of snacks, desserts and drinks.
3. Survival Rations: These are rations designed specifically for survival situations, where the soldier needs to feed for an extended period without access to additional supplies. They tend to be more compact and lighter, and can include dried foods, instant soups, water purification tablets, survival bars, packaged chocolate, coffee and tea.
4. Emergency rations: These are rations intended for situations of natural disasters or humanitarian crises. These rations are similar to survival rations, but are designed to meet a person's basic needs for a short period of time. They typically contain canned foods, energy bars, bottled water, and other essentials.

It is important to note that the exact types and specifications of military rations can vary between different countries and different branches of the armed forces. Additionally, over time, improvements and changes are made to rations to meet the changing needs of soldiers in the field.