Simple NHibernate Architecture

using System;
using System.Collections.Generic;
using System.Text;
using Shared.NHibernateDAL;
using NHibernate;

namespace Business
{
	public class Product : BusinessObject<Product>
	{
		public Product()
		{
			this._name = null;
			this._weight = 0;
		}

		private string _name;
		private decimal _weight;

		public virtual decimal Weight
		{
			get { return _weight; }
			set { _weight = value; }
		}

		public virtual string Name
		{
			get { return _name; }
			set { _name = value; }
		}

		public static List<Product> Select()
		{
			ISession session = NHibernateSessionManager.Instance.GetSession();
			IQuery query = session.CreateQuery("from Product");
			return (List<Product>)query.List<Product>();
		}

		public void OutterTransaction()
		{
			using (TransactionBlock tran = new TransactionBlock())
			{
				Product p1 = new Product();
				p1.Name = "Product 1";
				p1.Weight = 10;

				p1.Save();

                //Call another method with a transaction block
				InnerTransaction();

				tran.IsValid = true;
                // On the dispose call the transaction is commited if all transaction blocks are valid
			}
		}
        		
		private void InnerTransaction()
		{
			using (TransactionBlock tran = new TransactionBlock())
			{
				Product p2 = new Product();
				p2.Name = "Product 2";
				p2.Weight = 10;

				p2.Save();				

				tran.IsValid = true;
			}
		}
	}
}