Apple is expected to debut its 27-inch iMac with Retina quality display during its special media event on Thursday, which should ship before the end of the year.

A next generation iPad Air should also be on hand at the event, according to a research note by KGI analyst Ming-Chi Kuo and obtained by AppleInsider.

Kuo believes the highly-anticipated 27-inch Retina iMac will definitely be revealed at the event, though a 21-inch option is also in the works and should debut sometime in 2015.

The analyst said that Apple started on the 27-inch option before the 21-inch version since developing two different sized high-resolution panels is a demanding task.

The 27-inch options should feature 5K display, though exact specifications have not been confirmed by Apple yet.

Code discovered in an OS X 10.10 Yosemite beta back in June pointed to 6,400-by-3,600-pixel screen resolutions, according to AppleInsider.

Despite all the buzz for the Retina iMac, Kuo believes the iPad Air will steal the show, even though production issues could hurt a massive launch.

Poor yield rates associated with the tablet's anti-reflective screen coating have delayed manufacturing, causing a downgrade in shipments to around 7 and 9 million units, instead of the 12 million units shipped with the first iPad Air in 2013.

The iPad mini with Retina display is unlikely to see a major revision this year. Apple is focused though on a rumored 12.9-inch device to be released sometime in 2015, according to AppleInsider.

Kup doesn't think that Apple is planning on announced a new MacBook Air hardware at the event however, despite recent rumors.

The company is expected to announce public availability of OS X Yosemite, the next-generation Mac operating system with enhanced interaction with iOS devices.

There is a good chance Apple will launch Apple Pay at the media event, which was promised to be released in October, which could also mean the launch of iOS 8.1.

See Now: OnePlus 6: How Different Will It Be From OnePlus 5?