diff --git a/extensions/openpower-pels/mru.hpp b/extensions/openpower-pels/mru.hpp
new file mode 100644
index 0000000..8ad3e3c
--- /dev/null
+++ b/extensions/openpower-pels/mru.hpp
@@ -0,0 +1,122 @@
+#pragma once
+
+#include "stream.hpp"
+
+namespace openpower
+{
+namespace pels
+{
+namespace src
+{
+
+/**
+ * @class MRU
+ *
+ * This represents the MRU (Manufacturing Replaceable Unit)
+ * substructure in the callout subsection of the SRC PEL section.
+ *
+ * Manufacturing replaceable units have a finer granularity than
+ * a field replaceable unit, such as a chip on a card, and are
+ * intended to be used during manufacturing.
+ *
+ * This substructure can contain up to 128 MRU callouts, each
+ * containing a MRU ID and a callout priority value.
+ */
+class MRU
+{
+  public:
+    /**
+     * @brief A single MRU callout, which contains a priority
+     *        and a MRU ID.
+     *
+     * The priority value is the same priority type character
+     * value as in the parent callout structure. For alignment
+     * purposes it is a 4 byte field, though only the LSB contains
+     * the priority value.
+     */
+    struct MRUCallout
+    {
+        uint32_t priority;
+        uint32_t id;
+    };
+
+    MRU() = delete;
+    ~MRU() = default;
+    MRU(const MRU&) = default;
+    MRU& operator=(const MRU&) = default;
+    MRU(MRU&&) = default;
+    MRU& operator=(MRU&&) = default;
+
+    /**
+     * @brief Constructor
+     *
+     * Fills in this class's data fields from the stream.
+     *
+     * @param[in] pel - the PEL data stream
+     */
+    explicit MRU(Stream& pel);
+
+    /**
+     * @brief Flatten the object into the stream
+     *
+     * @param[in] stream - The stream to write to
+     */
+    void flatten(Stream& pel);
+
+    /**
+     * @brief Returns the size of this structure when flattened into a PEL
+     *
+     * @return size_t - The size of the section
+     */
+    size_t flattenedSize() const
+    {
+        return _size;
+    }
+
+    /**
+     * @brief Returns the contained MRU callouts.
+     *
+     * @return const std::vector<MRUCallout>& - The MRUs
+     */
+    const std::vector<MRUCallout>& mrus() const
+    {
+        return _mrus;
+    }
+
+    /**
+     * @brief The type identifier value of this structure.
+     */
+    static const uint16_t substructureType = 0x4D52; // "MR"
+
+  private:
+    /**
+     * @brief The callout substructure type field. Will be 'MR'.
+     */
+    uint16_t _type;
+
+    /**
+     * @brief The size of this callout structure.
+     */
+    uint8_t _size;
+
+    /**
+     * @brief The flags byte of this substructure.
+     *
+     * 0x0Y: Y = number of MRU callouts
+     */
+    uint8_t _flags;
+
+    /**
+     * @brief Reserved 4 bytes
+     */
+    uint32_t _reserved4B;
+
+    /*
+     * @brief The MRU callouts
+     */
+    std::vector<MRUCallout> _mrus;
+};
+
+} // namespace src
+} // namespace pels
+} // namespace openpower