Cannot see FirstOrDefault

Any Help is much appreciated guys!

under GetProductByID, i am getting an error saying "int does not contain a definition for FirstOrDefault".

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using HomebaseSystemNew.Models;

namespace HomebaseSystemNew.Controllers
  {
    public class ProductRepository
   {

    public ProductsController GetProductID(int Pid)
        {
          Product db = new Product();

          return db.Pid.FirstOrDefault(db => db.Pid == Pid);
        }


   }




   }