With WWDC 2013 set to kick off in less than a week with an Apple keynote on 10 June, speculation about what to expect from the event has been hot topic. It is widely expected that we will see a MacBook refresh, and allegedly leaked SKUs have added evidence to that rumour this week.

9To5Mac reports that it has received a set of SKUS that are believed to belong to an Apple laptop that comes in two sizes. The codes are as follows:

MD711LL/A — Better — USA

MD712LL/A — Best – USA

MD760LL/A — Better – USA

MD761LL/A — Best – USA

These four codes could represent four new MacBook Pro or MacBook Air models, with two different screen sizes and differing internal specifications.

It is not clear which of Apple's MacBook lineups these SKUs belong to, but it has been suggested that Apple will be refreshing its MacBook Pro with Retina display and its MacBook Air ranges at WWDC this year. 

Currently, the MacBook Air is available in four configurations, two with 11in displays and two with 13in displays. The Retina MacBook Pro comes in two 13in models and two 15in models.

MacBook Pro and MacBook Air stock has been running low over the past few weeks, also indicating that an update is imminent.

Additionally, 9To5Mac has received three more unidentified SKUs:

ME177LL/A — Better — USA

ME182LL/A — Best — USA

ME918LL/A — Good — USA

As well as new MacBooks, Apple is also rumoured to be launching a new Mac Pro at WWDC, and possibly also refreshed Mac mini and Apple TV. See: New Mac Pro release date, rumours and leaked images

It's pretty certain that we'll be getting our first look at iOS 7 and Mac OS X 10.9 at the event too.  See: What to expect from Apple at WWDC 2013

See: MacBook Air (2013) review.

See also:

iPhone 6 rumours: 'Leaked iPhone 5S parts' show new gold colour option

New Mac Pro at WWDC… or this autumn, Thunderbolt expansion and other details leak

iPad 5 production to begin July, iPad mini 2 delayed - report