Prisoners and Penetera's security guard
Prisoner Transporter is a type of Spaceship used to transport criminals.
Whenever a criminal or smuggler is caught, they are immediately scort into a Prisoner Transporter, and than transported to the Penetera Prison Facility on Penetera. Vala's team was caught and scorted on one of this ships into the prison on Penetera. (SG1: "Vala Mal Doran 2")