diff --git a/era/era_detail.cc b/era/era_detail.cc
new file mode 100644
index 0000000..43fbc51
--- /dev/null
+++ b/era/era_detail.cc
@@ -0,0 +1,36 @@
+#include "era/era_detail.h"
+
+#include <stdexcept>
+
+using namespace base;
+using namespace era;
+
+//----------------------------------------------------------------
+
+namespace {
+	le32 pack_hash_detail(uint32_t hash1, uint32_t hash2, uint32_t nr_probes) {
+		throw std::runtime_error("not implemented");
+	}
+
+	void unpack_hash_detail(le32 packed, uint32_t &hash1, uint32_t &hash2, uint32_t &nr_probes) {
+		throw std::runtime_error("not implemented");
+	}
+}
+
+void
+era_detail_traits::unpack(disk_type const &disk, value_type &value)
+{
+	value.nr_bits = to_cpu<uint32_t>(disk.nr_bits);
+	unpack_hash_detail(disk.hash_fns_and_probes, value.hash1, value.hash2, value.nr_probes);
+	value.bloom_root = to_cpu<uint64_t>(disk.bloom_root);
+}
+
+void
+era_detail_traits::pack(value_type const &value, disk_type &disk)
+{
+	disk.nr_bits = to_disk<le32>(value.nr_bits);
+	disk.hash_fns_and_probes = pack_hash_detail(value.hash1, value.hash2, value.nr_probes);
+	disk.bloom_root = to_disk<le64>(value.bloom_root);
+}
+
+//----------------------------------------------------------------
diff --git a/era/era_detail.h b/era/era_detail.h
new file mode 100644
index 0000000..1b907fb
--- /dev/null
+++ b/era/era_detail.h
@@ -0,0 +1,36 @@
+#ifndef ERA_DETAIL_H
+#define ERA_DETAIL_H
+
+#include "base/endian_utils.h"
+
+//----------------------------------------------------------------
+
+namespace era {
+	struct era_detail_disk {
+		base::le32 nr_bits;
+		base::le32 hash_fns_and_probes;
+		base::le64 bloom_root;
+	};
+
+	struct era_detail {
+		uint32_t nr_bits;
+
+		uint32_t hash1;
+		uint32_t hash2;
+		uint32_t nr_probes;
+
+		uint64_t bloom_root;
+	};
+
+	struct era_detail_traits {
+		typedef era_detail_disk disk_type;
+		typedef era_detail value_type;
+
+		static void unpack(disk_type const &disk, value_type &value);
+		static void pack(value_type const &value, disk_type &disk);
+	};
+}
+
+//----------------------------------------------------------------
+
+#endif