diff --git a/parallel_hashmap/phmap.h b/parallel_hashmap/phmap.h
index 6ba25bc..1803bdf 100644
--- a/parallel_hashmap/phmap.h
+++ b/parallel_hashmap/phmap.h
@@ -4387,6 +4387,21 @@ namespace hashtable_debug_internal {
 
 // --------------------------------------------------------------------------
 // --------------------------------------------------------------------------
+
+template <typename Set>
+struct HashtableDebugAccess<Set, phmap::void_t<typename Set::parallel_hash_set>> {
+    using Traits = typename Set::PolicyTraits;
+    using Slot = typename Traits::slot_type;
+    using EmbeddedSet = typename Set::EmbeddedSet;
+
+    static size_t GetNumProbes(const Set& set, const typename Set::key_type& key) {
+        size_t hashval = set.hash(key);
+        auto& inner = set.sets_[set.subidx(hashval)];
+        auto& inner_set = inner.set_;
+        return HashtableDebugAccess<EmbeddedSet>::GetNumProbes(inner_set, key);
+    }
+};
+
 template <typename Set>
 struct HashtableDebugAccess<Set, phmap::void_t<typename Set::raw_hash_set>> 
 {