Kuo says the specs for the device were decided in 2011 and are "unlikely to abruptly change" due to the popularity of 5-inch devices.
The new phone is said to have a "super-thin plastic casing mixed with glass fiber" that makes it stronger, thinner and lighter than typical plastic casings. The plastic case is expected to between 0.4 and 0.6 millimeters thick compared to the average case at 0.7 to 1.0 millimeters thick. It will come in a range of four to six colors, similar to the iPod.
Apple is said to have contracted with Foxconn as well as Green Point of the Jabil group for its strong and thin iPhone plastic casings. Hon Hai will both build casings and assemble the phones, while Jabil is expected to provide its casings to Pegatron, which will assemble the remaining iPhones. The analyst reported earlier this week that Apple was likely to diversify manufacturers for both its low-cost and legacy iPhones.
Kuo recently predicted that Apple would unveil the low cost iPhone and an iPhone 5S with fingerprint scanner in June.