What is the difference between <location> VAC and <location>?

What is the difference between <location> VAC and <location>?

There are 2 type of visa appointments.
  1. Regular - If you are visiting US for the first time. 
  2. Dropbox - If you already got a US visa approved in the first attempt.
For Regular appointment types, the applicant has to book 2 appointments.
  1. Appointment for biometrics (OFC) - The locations in the dropdown will have "VAC" suffixed for these. This is the appointment for an office, where you submit your DS-160 details and fingerprints.
  2. Consular Appointment (CA) - This is the appointment to enter the US consulate where you actually face the Interview with a Visa officer.
For Dropbox appointment types, the applicant need only one appointment to submit the visa documents. Basically, you are eligible for interview waiver.