The manufacturing process for the jet black iPhone 7 is a little different from the process for other units and that has contributed to a global shortage of those devices. According to KGI analyst Ming-Chi Kuo, just 30-70% of jet black iPhones pass Apple's inspection, meaning the rest need to be reworked.

Apple uses a multi-step anodization and polishing process to achieve the jet black external coating. When combined with fairly high demand for the units, consumers could wait months to get their hands on a jet black iPhone 7.

Current online orders may not ship for weeks and there are only a handful of retail Apple stores carrying jet black units.

While strong demand for the iPhone 7, particularly the iPhone 7 Plus, contributed to the current shortage, it's not the only factor.