diff --git a/parallel_hashmap/phmap.h b/parallel_hashmap/phmap.h
index f8de239..4636533 100644
--- a/parallel_hashmap/phmap.h
+++ b/parallel_hashmap/phmap.h
@@ -1466,6 +1466,15 @@ public:
         assert(!slot);
     }
 
+    template <class K = key_type, class F>
+    void emplace_single_with_hash(const key_arg<K>& key, size_t &hashval, F&& f) {
+        auto res = find_or_prepare_insert(key, hashval);
+        if (res.second)
+            lazy_emplace_at(res.first, std::forward<F>(f));
+        else
+            _erase(iterator_at(res.first));
+    }
+
 
     // Extension API: support for heterogeneous keys.
     //
@@ -3080,19 +3089,14 @@ public:
         typename Lockable::UniqueLock m(inner);
         return make_iterator(&inner, set.lazy_emplace_with_hash(key, hashval, std::forward<F>(f)));
     }
-
-    template <class K = key_type, class FExists, class FEmplace>
-    bool lazy_emplace_l(const key_arg<K>& key, FExists&& fExists, FEmplace&& fEmplace) {
-        typename Lockable::UniqueLock m;
-        auto res = this->find_or_prepare_insert(key, m);
-        Inner* inner = std::get<0>(res);
-        if (std::get<2>(res))
-            inner->set_.lazy_emplace_at(std::get<1>(res), std::forward<FEmplace>(fEmplace));
-        else {
-            auto it = this->iterator_at(inner, inner->set_.iterator_at(std::get<1>(res)));
-            std::forward<FExists>(fExists)(Policy::value(&*it));
-        }
-        return std::get<2>(res);
+    
+    template <class K = key_type, class F>
+    void emplace_single(const key_arg<K>& key, F&& f) {
+        auto hashval = this->hash(key);
+        Inner& inner = sets_[subidx(hashval)];
+        auto&  set   = inner.set_;
+        typename Lockable::UniqueLock m(inner);
+        set.emplace_single_with_hash(key, hashval, std::forward<F>(f));
     }
 
     // Extension API: support iterating over all values
@@ -3715,7 +3719,6 @@ public:
         return modify_if_impl<K, F, typename Lockable::UniqueLock>(key, std::forward<F>(f));
     }
 
-
     // if map contains key, lambda is called with the mapped value  (under write lock protection).
     // If the lambda returns true, the key is subsequently erased from the map (the write lock
     // is only released after erase).
@@ -3748,6 +3751,20 @@ public:
         return std::get<2>(res);
     }
 
+    template <class K = key_type, class FExists, class FEmplace>
+    bool lazy_emplace_l(const key_arg<K>& key, FExists&& fExists, FEmplace&& fEmplace) {
+        typename Lockable::UniqueLock m;
+        auto res = this->find_or_prepare_insert(key, m);
+        typename Base::Inner* inner = std::get<0>(res);
+        if (std::get<2>(res))
+            inner->set_.lazy_emplace_at(std::get<1>(res), std::forward<FEmplace>(fEmplace));
+        else {
+            auto it = this->iterator_at(inner, inner->set_.iterator_at(std::get<1>(res)));
+            std::forward<FExists>(fExists)(Policy::value(&*it));
+        }
+        return std::get<2>(res);
+    }
+
     // ----------- end of phmap extensions --------------------------
 
     template <class K = key_type, class P = Policy, K* = nullptr>
diff --git a/tests/parallel_flat_hash_set_test.cc b/tests/parallel_flat_hash_set_test.cc
index 3c193de..b1924bd 100644
--- a/tests/parallel_flat_hash_set_test.cc
+++ b/tests/parallel_flat_hash_set_test.cc
@@ -1,4 +1,5 @@
 #define THIS_HASH_SET  parallel_flat_hash_set
 #define THIS_TEST_NAME ParallelFlatHashSet
 
-#include "flat_hash_set_test.cc"
+#include "parallel_hash_set_test.cc"
+
diff --git a/tests/parallel_hash_map_test.cc b/tests/parallel_hash_map_test.cc
index 3bfb1e6..59d91d6 100644
--- a/tests/parallel_hash_map_test.cc
+++ b/tests/parallel_hash_map_test.cc
@@ -68,7 +68,7 @@ TEST(THIS_TEST_NAME, ThreadSafeContains) {
 
     {
         // --------------------
-        // test lazy__emplace_l
+        // test lazy_emplace_l
         // --------------------
         Map m = { {1, 7}, {2, 9} };
  
diff --git a/tests/parallel_hash_set_test.cc b/tests/parallel_hash_set_test.cc
new file mode 100644
index 0000000..0f0143b
--- /dev/null
+++ b/tests/parallel_hash_set_test.cc
@@ -0,0 +1,36 @@
+#ifndef THIS_HASH_SET
+    #define THIS_HASH_SET  parallel_flat_hash_set
+    #define THIS_TEST_NAME ParallelFlatHashSet
+#endif
+
+#include "flat_hash_set_test.cc"
+
+namespace phmap {
+namespace priv {
+namespace {
+
+TEST(THIS_TEST_NAME, ThreadSafeContains) {
+    // We can't test mutable keys, or non-copyable keys with ThisSet.
+    // Test that the nodes have the proper API.
+    using Set = phmap::THIS_HASH_SET<int>;
+
+    {
+        // --------------------
+        // test emplace_single
+        // --------------------
+        Set m = { {1}, {11} };
+ 
+        // emplace_single insert a value if not already present, else removes it
+        for (int i=0; i<12; ++i)
+            m.emplace_single(i, [i](const Set::constructor& ctor) { ctor(i); });
+        EXPECT_EQ(m.count(0), 1);
+        EXPECT_EQ(m.count(1), 0);
+        EXPECT_EQ(m.count(2), 1);
+        EXPECT_EQ(m.count(11), 0);
+    }
+
+}
+
+}  // namespace
+}  // namespace priv
+}  // namespace phmap