Love, love, love this collar! I have been looking for an LED collar for a while and was surprised to find this one at such a great price. I ordered a large since I have a bulldog with a rather large neck, it without a problem and now she can be seen easily at night. Primarily use th solid light setting but like that is has the option of flashing and so far the battery life has been great. Would absolutely recommend it to anyone who has a dog going outside at night.