Yes, you never know what you are going to get. It is a fun surprise. Somehow my dog knows that the box belongs to her when it comes in and she watches me cut it open. I usually let her see what's in it and she picks something out and runs off with it.
Yes, it is a surprise each month what you get. They are so fun to receive. I take my dog with to check the mail each day and he gets so excited when we open our mailbox and he has a BarkBox inside. He can hardly contain himself until we get back up to our apt to open it.