Ensure's your 5/8-inch (16 mm) hole is drilled properly. Highly recommended for Mini-Vapor Pin® sampling device installation. Ensure's your 5/8-inch (16 mm) hole is drilled properly. Highly recommended for Mini-Vapor Pin® sampling device installation. Drill a 5/8-inch (16mm) diameter hole through the slab and approximately 1-inch (25mm) into the underlying soil to form a void. Hole must be 5/8-inch (16mm) in diameter to ensure a seal. When installing the Mini-Vapor Pin® sampling device, the drilled hole must be perpendicular to the slab for the mandatory Secure Cover to seat correctly. It is strongly recommended that the Stick-Up Vapor Pin® drilling guide be used for this purpose.