What is a batch HIT?
A batch HIT is a task that you can preform over and over again. These are good when you are trying to get your numbers up. Batches are usually HITs that can be done within a minute or two. Some can even be completed in under 10 seconds. Their pay is usually not the best, but they will increase your approval percentage in case of a rejection.
An easy way to search for large batch HITs is to sort your search results with the "HITs Available (most first)" option. This is located on the left side of the screen above all of the HITs that are available to do.