A rig is a guaranteed flight hour pay for a non-flying time spent at work. A 1:2 rig means you get paid 1 flight hour for each 2 hours of duty.

Duty Rig (typically 1:2): Guarantees that you get paid for time actually spent on duty. A 6 hour day would guarantee 3 hours flight pay, even if you don't fly at all. If you fly more than 3, you get paid what you flew.

Trip Rig (typically 1:3): More of a major airline thing. Guarantees pay for time spent away from base. This prevents the company from giving a 38 hour layover in some cr@phole like TUS with no pay.

Daily Rig (typically 3-4 hours): If you go to work for any reason, including showing up for a cancelled flight, you get paid at least this much. Can also function as a trip rig.

Ready Reserve and deadhead usually credit either full or half flight pay, depending on the airline.

If you have no rigs at all (Mesa) the company can have you show up, do a 30 minute flight, sit around some airport for 6 hours, do another 30 minute flight, go to a hotel, hang out for 28 hours, then do a 30 minute flight home...all of which pays 1.5 hours for 2.5 days spent "at work".

Rigs and other workrules are FAR more important than hourly scales in the regional world...unfortunately the info web sites tend to focus on hourly pay scale instead of work rules.