Use Of Join in Linq

LimeDataClassesDataContext db = new LimeDataClassesDataContext();

IEnumerable<Object> specialOffer = (from p in db.tblProducts

join ol in db.tblProductOfferLookups on p.ProductId equals (long)ol.ProductID

join o in db.tblSpecialOffers on (long)ol.OfferID equals o.Offerid

where o.IsActive == true && p.IsSpecialOffer == true && p.IsActive == true && p.IsDeleted == false

select o).Distinct();

return specialOffer;