TSA Pre-Check is debuting at 60 airports and expanding at the 40 airports that already have it, including Minneapolis-St. Paul International.

But what the heck is Pre-Check? Before you decide whether to apply, make sure you understand how the program works and whether it’s for you. If you fly a lot domestically, I’d recommend it.

What it is: The Transportation Security Administration Pre-Check lanes are fast security lanes at certain airports that speed you through security without some of the other hassles.

Who can use it: Until now, only certain elite-level passengers and people who have Global Entry or Nexus-trusted traveler status (see more below). Later this year, anyone will be able to apply for Pre-Check clearance, the TSA announced Sept. 4.

Which airlines participate: Not all of them cooperate in this program, so if you fly an airline such as Spirit, you can’t use the lane. Participating airlines are Delta, American, United, US Airways, Alaska, Hawaiian and Virgin America. Southwest and Jet Blue are preparing to join the program. Some airlines, such as Delta, provide a helpful feature — when you print out your boarding pass, it tells you whether you can use the Pre-Check lane.

How to apply: The application is not ready yet, but will cost $85. It will involve an online application plus a personal visit and fingerprint scan. Clearance is good for five years. You do not need a passport to apply. Eligibility rules are not ready, but a felony record disqualifies you for other trusted traveler programs, so that could likely be the same case here.

Where to get the application: Check www.tsa.gov/tsa-precheck for updates.

How airlines know you have Pre-Check clearance: The TSA will give you a known-traveler number. Each time you make a reservation, enter the number. You also can add your known-traveler number to your airline frequent flier profile, and it will be automatically added to reservations you make.

Who can go with you: Children 12 and under will be able to use the line if the adult they are traveling with has Pre-Check clearance.

What it won’t do: TSA Pre-Check clearance is good only at certain domestic airports for passengers headed to domestic or international destinations. It also does not guarantee easy screening. There is a random quality about it, so even those who qualify to use the lane may sometimes be directed to the regular security lane.

How Pre-Check differs from other trusted traveler programs: U.S. Customs and Border Protection has one called Global Entry ($100, www.globalentry.gov ) that I recommend for anyone who travels internationally. Global Entry is good at both TSA Pre-Check lanes and at U.S. Immigration/Customs when returning from abroad. Global Entry also is good at Nexus lanes coming into the United States from Canada.

Speaking of Nexus: Nexus is clearance program familiar to travelers who drive back and forth to Canada a lot. Nexus also can be used at TSA Pre-Check lanes, provided the government has your fingerprints on file.

The downside of Pre-Check: If millions get clearance, it is possible it could make Pre-Check lines as long as regular lines. One assumes the TSA would jigger the configuration of its lines depending on the number of passengers with Pre-Check.