Google officially unveiled its new Pixel 6 and Pixel 6 Pro smartphones today (October 19). One detail that was not fully unveiled, however, was the price difference for the Pixel 6. Google Pixel 6 pre-orders at the Google Store and T-Mobile start at $599.99 for the Pixel 6 and $899.99 for the Pixel 6 Pro.

Reservations on Verizon, however, start at $699.99 for the base model. AT&T, on the other hand, sells Google's flagship models for as high as $739.99 and $939.99. Sure, there are plenty of aggressive campaigns to drive prices down, but if you are wondering why there is such a dramatic price difference, the answer is simple.

As this Google chart explains, there are several Pixel 6 models available for pre-order: the GB7N6 is the basic model ($599), which does not support millimeter wave 5G; it only supports the Sub-6GHz band; the GB7N6 is the basic model ($599), which does not support millimeter wave 5G; the GB7N6 is the basic model ($599), which supports the Sub-6GHz band.

The G9S9B, on the other hand, supports millimeter wave. This is the model sold on Verizon and AT&T, which is why Pixel 6 models for these carriers are more expensive than Google and T-Mobile models. (All Pixel 6 Pro models sold in the US support mmWave.)

The 5G standard consists of low-band, mid-band, and high-band frequency bands. As a result, 5G networks operate at different frequencies, sub-6 GHz and mmWave (20-60 GHz) at the low and high band ends.

mmWave 5G offers exponentially faster speeds than Sub-6GHz 5G, but is more limited in terms of communication range. In other words, cell phones supporting mmWave 5G must be installed in some proximity to a 5G tower to enjoy the higher speeds.

This may work in metropolitan areas where multiple towers are spread throughout the city, but is unlikely in rural areas. As a result, millimeter wave 5G has been slow to spread and is only available in a few cities.

Not sure which Pixel 6 is right for you? See our Google Pixel 6 review and our Google Pixel 6 Pro review.