These batteries work well last longer than others that we have used in the past good valueThe doctor put these batteries in when I bought the hearing aids, and I've continued with them. Tied a few other batteries over the years, but always come back to these.The batteries are a great value for the price.Have purchased this brand several times. Very satisfied and exceptionally satisfied with seller and communicationI've used these batteries before. I've used the 312's and now I'm using the 13. I've got up to 7 days of life out of the 13. If you change setting a lot in your hearing aid it drops the life a little. However, on the whole there great and the price is much better then brick and mortar stores.This battery lasts for different number of days depending on length used during 24 hour activity. They are convenient to place in a pocket in a purse for use and replacement as needed. My average is 10 days to two weeks. And they are a bargain compared to market place packets. This is a far less expensive item than over-the-counter purchase or at a your service supplier office. I expect to go till mid 2020 with the thirty batteries.If I am fortunate, the batteries may even last until 2021. That will be awesome.Been buying this battery for years. This must be my 4th or 5th order and will continue to purchase. It does what it is supposed to do and for a good price.Works as advertised. good price.Batteries pour appareil auditif,Lorsque qu'il est écrit 30 X taille P13. Voulez-vous dire 30 cartons de 6 batteries.pour le prix que j'ai payé 67.00 taxe incluse. Si c'est çà il me manque 30 autres cartons de 6 batteries.J'ai reçu seulement 15 cartons .J'aimerais avoir l'explication. Merci à l'avance.Hearing aids, last longer