The compact stapler style slot punch is an economical choice for punching your ID cards or credentials.  Punches a rectangular hole with rounded edges that is 1/2" x 1/8".  It will punch one laminated or PVC card per punch. 

The side guide can be set to ensure that your slot is centered on your card.  The depth guide adjusts to control how far into the margin your slot is punched.  Punched shavings are collected in the rubberized base thus keeping your work area clean.