Actual hourly: $42.79/hr over 758 HITs (yes this is real)

TL;DR: big brainless bountiful batch

This batch pays well for the dumbest reason. The requester is throwing all of their object names into each image and seeing which one applies, which results in 99% of the given objects not being in the image. This means that most of the time, you can comfortably select 'No' for all the objects in the image.

There is only one image in each HIT, and most of the images are typical everyday images. They are simple most of the time, and you can almost always figure out the setting of the image, which can make determining objects even easier.

They provide keybinds for the HIT, and you can rifle through the objects super quick with these keybinds. With multiple tabs and the provided keybinds, you can make this batch extremely lucrative.

The requester has consistently posted work around 10AM and 9PM CST every day. When they post work, they drop big batches and smaller batches for several hours at a time, which means it should be available for everyone.

All of the above make the batch pay as well as it does, and it makes for a good batch to increase your numbers on as well.

The requester uses a somewhat closed qual system. You're given a 'tutorial' HIT, then the HIT after that is what they use to screen for good workers. If you don't submit adequate work, you'll be locked out of the requester's HITs until they post a new HIT with [NEW BATCH]. This requester generally knows what they're doing and how to get the best data out of mturk.