Phonak Naida UPs are for severe to profound hearing loss. If you have mild to moderate loss they are going to be much too powerful for you and likely to result in further damage to your hearing. Even Naida SPs are for moderately severe to profound loss. My advice is find something else much more suited to your hearing loss! They are also generally used with a custom ear mould, so if it is a small open fit hearing aid you are looking for, these are not the right ones for you. You might also find that the internal noise generated by the hearing aids' powerful amplifiers would be irritating to you, although it would be unnoticed by those with a loss for whom these aids were intended. Furthermore, I would imagine any audiologist you took them to for programming would question why you are wanting to use, what is effectively, the most powerful hearing aids on the market for only a mild to moderate loss.
Also, Naida UPs have a frequency range of 100-4900 Hz, whereas hearing aids for mild to moderate loss generally go up as far as 8000 Hz. This is because most people with severe to profound loss have little or no high frequency hearing and would not benefit from the extended frequency range. Another reason, perhaps, why a different hearing aid would be better for you, especially if your loss is mostly in the high frequencies.