Honza, I wouldn't dare. There are really a lot of hearing defects, you can't take it just because your grandmother is old. She should first be examined by a doctor and recommend exactly which hearing aids will be suitable for her. Then only choose the hearing aids. If the insurance company pays for one hearing aid on the recommendation of a doctor, up to the amount of CZK 5,100, then the cheap one from the net will probably not be the right thing to do. My grandmother also heard poorly and received a hearing aid from a doctor. In the end, the sound disturbed her so much that it hurt that she never wore it anyway.