If so-called basic economy fares aren’t yet a pervasive fact of travel life, they soon will be.

The stripped-down fares, which Spirit famously refers to as Bare Fares, are designed to appeal to the most price-sensitive consumers, who are willing to forego such niceties as seat selection, boarding priority, changeable tickets, and so on in exchange for rock-bottom prices.

Among the full-service carriers, Delta was the first to introduce what it called Basic Economy, citing the need to compete with the likes of Spirit and Frontier. While Delta initially only offered them in very few markets, today they are much more widely available.

American and United have been slower to bring unbundled fares to market, but both recently signaled their intentions to do so early in 2017. And today, for the first time, United provided details of its new fares.

As did Delta, United is promoting its Basic Economy fares as providing “more choice for customers”:

To further meet customers’ needs and provide more options to price-sensitive travelers, the company announced the introduction of Basic Economy fares. This new offering provides customers the option of paying the lowest fares to their destinations, while still receiving the same standard economy experience, including food, beverage, Wi-Fi and personal device entertainment, with a few key differences.

But oh, those differences! Here’s a partial list of what Basic Economy passengers don’t get:

• No advance seat assignments
• Carry-on bags limited to one “personal item” (waived for elites)
• No ticket changes
• No elite-qualifying miles, segments, or dollars
• No upgrades

Notably, United’s basic fares are even more basic than Delta’s, which don’t restrict carry-ons or elite miles. Although it seems patently unfair, the loss of elite miles is probably a non-issue for most of the targeted customers. But just one small carry-on? That’s harsh, and clearly designed to force passengers to pay to check their bags. Which will offset at least some of the savings that basic fares are supposed to offer.

United has taken bare fares beyond bare; their new Basic Economy product should be called Nasty Fares.

Reader Reality Check

Has United taken unbundling too far?

After 20 years working in the travel industry, and almost that long writing about it, Tim Winship knows a thing or two about travel. Follow him on Twitter @twinship.

This article first appeared on SmarterTravel.com, where Tim is Editor-at-Large.