pettechproducts.us at 8543 Twickenham Terrace, Harrisburg, North Carolina.

We bought 2 thru Amazon and they worked great for about 1 year. We loved them! Then the on/off button wore out on both of them within days of each other (our dogs DO chew on the other's collar, evidently about equally) so we ended up requesting replacement collars. We contacted seller thru Amazon and replacements were to us within days. On our big bad dogs, lol, and working again! I have to say I am not able to access their website at all for some reason on computer or Android, but access thru Amazon worked like a charm!