When most people talk about Polaroid cameras, they mean the popular and relatively cheap models of the 1980s and 1990s that used film packs with integral batteries that were designated the 600 series. The "instant" prints measure 79mm (3.1") square with a white border around them and take around 3 minutes to fully develop at 70°F (21°C). The film has an ISO rating of 640. The film was branded with several different names over the years, including "Extreme 600" and "Notepad". A high definition "professional" film named "779" could also be used with cameras from the 600 series. Some of the cameras had 'sonar' autofocus and/or featured glass lenses, but most had plastic lenses with a fixed focus of around 4 feet. A "close-up" lens was often included, but this took the form of a simple plastic meniscus that slid into place. Many of the models are functionally identical to others but have different coloured fascia, names and stickers according to marketing territory. Several models were limited editions with tie-ins to icons of popular culture, such as Barbie or the Spice Girls, while other versions were promotional items made for corporate entities and are now highly collectible thanks to their rarity.