Save 3 decimal places to sqlServer

Question

Personal I have to save 3 decimal places in my database SQLSERVER, however this saving only 2 houses for example I have a value 0.456 and when saving is 0.450 in the code :

using System.ComponentModel.DataAnnotations;

    public class TB_ItensPedidoCompra
    {
    public decimal ValorUnitario{ get; set; }

    [MaxLength(10)]
    public string TipoSelecionado { get; set; }

 }

In my bank layer it’s like this:

 bdProduto.ValorUnitario = Convert.ToDecimal(vlUnitario);

the value up to vlUnitario enough 0.456, but when saved is 0.450

Could someone help me

in my bank edited

Nome da coluna = ValorUnitario  Tipo de Dados = decimal(18, 4)