When DVD was still a new format, there were very few replicators that were capable of pressing dual layer discs. Because of the demand, these replicators did 99.9% of their work for mainstream studios (no adult). For movies over 2 hours long, or movies that contained a lot of extras, "flippers" were the only option.
Now, most replicators are able to press dual layer discs, so flippers are much more uncommon.


