Like bottles of salad dressing, these come with a dispensing cap that fits inside the neck of the bottle. It is not necessary to use these inserts. The bottles don't leak with or without the extra insert. I use the insert for lotion but not for shampoo or conditioner. I thought about using these bottles for my homemade salad dressing, but they are recyclable number 1. Numbers 2, 4, and 5 are preferred for food. I love the 8 oz size for travel.