I originally bought anther Banglijian model, in August, 2019, but the amplification was too much. I returned it and had an immediate refund. Kaven suggested that I try the Ziv-201 model, which I bought in September, 2019 and a second one in December, 2019. Because I wear glasses I had to use the thin tube, but it was too short to fit in my ear properly. Kaven sent me directions, with pictures, which showed me how to lengthen the tube. At first I thought that I wasn't going to waste my time, but See full review