AB drills, also known as Aurora Borealis drills, are a type of diamond painting drill that have a special coating that reflects different colors of light, creating a unique and vibrant effect. In contrast, ordinary drills are regular diamond painting drills that do not have this coating.

The AB coating on these drills gives them a shimmering and iridescent effect, which can add an extra level of sparkle and depth to your diamond painting. However, because of the added coating, AB drills can be slightly more expensive than ordinary drills.

It's important to note that the AB coating on drills is not permanent and can wear off over time, especially if the painting is handled frequently or exposed to moisture or heat. Additionally, some people may prefer the look of regular drills over AB drills, depending on their personal style and preferences.

Overall, the choice between AB drills and ordinary drills comes down to personal preference and budget. If you want a diamond painting with a unique and eye-catching look, AB drills may be a good choice, but if you prefer a more traditional look or want to save money, regular drills may be a better option.