Thread Synchronization in C# .NET

using System;
using System.Threading;

class Thread_Sync
    {
        public void PrintNumbers()
        {
            lock (this)
            {
                for (int i = 1; i <= 10; i++)
                {
                    Console.WriteLine(i);
                    Thread.Sleep(500);
                }
            }
        }
        static void Main(string[] args)
        {
            Thread_Sync t = new Thread_Sync();

            Thread t1 = new Thread(t.PrintNumbers);
            Thread t2 = new Thread(t.PrintNumbers);

            t1.Start();
            t2.Start();
        }
    }