I do not know yet if this patch is effective or not but I am appalled by the amount of delivery charges (6.90) while the product happened to me in a normal envelope with a stamp to mail Ecopli 20g ... A delivery invoice is more than the actual amount 6. Suffice to say that the product costs 26 ... not 20 ... I find it displayed dishonest process ... I hope the product quality is real because frankly, there mm, 20 pr a small round cardboard ... Must believe ...