My hearing aids are Siemens 23SP (I have no useful residual hearing). The tubes and domes supplied with these aids as standard are rather uncomfortable, so I found that Hearing direct would send me selection packs and samples. As a result, I was able to come up with a much more satisfactory combination which is so comfortable and works so well that I am not aware that I am wearing aids. Since then (for 2 years) I have been able to re-order with confidence. I also purchase my batteries (Duracell) from Hearing Direct. They each last 3 weeks, using them 14 hours a day. I am really pleased I found Hearing Direct.