this one works! I could instantly tell they werent natural quartz and were probably glass. I am new to this type of camera, but do have much experience with smart cams that are used in the home. I wore these around the house to break them in, and I am confident they will more than do the job! E la seconda che compro per il suo prezzo è più che buona It would be much easier to install if the decal didn?t go right around the words. Having used them for the best part of a week, I?ve been very impressed with both the sound quality and the connectivity. I dont wear flip flops and have semi-flat feet. Will have a mount to a flat bar and or in a clear tube to protect it from damage. Clippers are too big and I?m not paying to have him groomed, also not spending $50 for the same product but ?for dogs?.