Confortable if you have a mask with long bands
Been using a lot of different strap extenders for a good time and they all work but It depends your face and mask size. I'll explain, mask don't tell you size but some of them come with long band or shorter bands. for me it works with long elastic band mask, With the shorter band the corners of the extender bends and I get the mask loose. They are comfortable and I can do my 8 hour shift with no problem. They come in different colors so if you like to combine they have set with different  colors.
Rating: 4 stars