var product = new List<ProductCrp>
        {
            new ProductCrp {
                Strucutre = new StructureItem() {
                    CheckList = new CheckList() {
                        Checks = new List<Check>
                        {
                            new Check { NumberAsInt = "149" },
                            new Check { NumberAsInt = "260" },
                            new Check { NumberAsInt = null }
                        }
                    }
                }
            },
            new ProductCrp {
                Strucutre = new StructureItem() {
                    CheckList = new CheckList() {
                        Checks = new List<Check>
                        {
                            new Check { NumberAsInt = "261" },
                            new Check { NumberAsInt = "150" },
                            new Check { NumberAsInt = "260" }
                        }
                    }
                }
            }
        };

        string[] numbers = { "149" };

foreach (var item in product)
        {
            item.Strucutre.CheckList.Checks = item.Strucutre.CheckList.Checks.Where(w => numbers.Contains(w.NumberAsInt)).Select(w => w);
        }