diff --git a/EpinelPS/LobbyServer/Character/ChangeSynchroDevice.cs b/EpinelPS/LobbyServer/Character/ChangeSynchroDevice.cs
index af18814..c37b478 100644
--- a/EpinelPS/LobbyServer/Character/ChangeSynchroDevice.cs
+++ b/EpinelPS/LobbyServer/Character/ChangeSynchroDevice.cs
@@ -1,4 +1,5 @@
-using EpinelPS.Utils;
+using EpinelPS.Database;
+using EpinelPS.Utils;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -48,6 +49,9 @@ namespace EpinelPS.LobbyServer.Character
             {
                 response.Slots.Add(new NetSynchroSlot() { Slot = item.Slot, AvailableRegisterAt = item.AvailableAt, Csn = item.CharacterSerialNumber });
             }
+            
+            JsonDb.Save();
+            
             await WriteDataAsync(response);
         }
     }
diff --git a/EpinelPS/LobbyServer/Character/RegisterSynchroDevice.cs b/EpinelPS/LobbyServer/Character/RegisterSynchroDevice.cs
index 4fe3c8e..43b40c9 100644
--- a/EpinelPS/LobbyServer/Character/RegisterSynchroDevice.cs
+++ b/EpinelPS/LobbyServer/Character/RegisterSynchroDevice.cs
@@ -1,4 +1,5 @@
-using EpinelPS.Utils;
+using EpinelPS.Database;
+using EpinelPS.Utils;
 
 namespace EpinelPS.LobbyServer.Character
 {
@@ -41,6 +42,7 @@ namespace EpinelPS.LobbyServer.Character
                 }
             }
            
+            JsonDb.Save();
 
             await WriteDataAsync(response);
         }
diff --git a/EpinelPS/LobbyServer/Character/SynchroAddSlot.cs b/EpinelPS/LobbyServer/Character/SynchroAddSlot.cs
new file mode 100644
index 0000000..4cd919f
--- /dev/null
+++ b/EpinelPS/LobbyServer/Character/SynchroAddSlot.cs
@@ -0,0 +1,49 @@
+using EpinelPS.Database;
+using EpinelPS.Utils;
+
+namespace EpinelPS.LobbyServer.Character
+{
+    [PacketPath("/character/synchrodevice/addslot")]
+    public class SynchroAddSlot : LobbyMsgHandler
+    {
+        protected override async Task HandleAsync()
+        {
+            var req = await ReadData<ReqSynchroAddSlot>();
+            var user = GetUser();
+            var response = new ResSynchroAddSlot();
+
+            var slot = user.SynchroSlots.FirstOrDefault(x => x.Slot == req.Slot);
+            if (slot != null)
+            {
+                response.Slot = new NetSynchroSlot
+                {
+                    Csn = slot.CharacterSerialNumber,
+                    Slot = slot.Slot,
+                    AvailableRegisterAt = slot.AvailableAt
+                };
+            }
+            else
+            {
+                var newSlot = new NetSynchroSlot
+                {
+                    Csn = 0,
+                    Slot = req.Slot,
+                    AvailableRegisterAt = 0
+                };
+
+                user.SynchroSlots.Add(new SynchroSlot()
+                {
+                    Slot = newSlot.Slot,
+                    CharacterSerialNumber = newSlot.Csn,
+                    AvailableAt = newSlot.AvailableRegisterAt
+                });
+
+                response.Slot = newSlot;
+            }
+
+            JsonDb.Save();
+
+            await WriteDataAsync(response);
+        }
+    }
+}