He takes a laser pointer out of his pocket and offers it to her.

"This is an ultraviolet laser. Shine it on a vampire's bare skin and they will catch fire. If they don't manage to put themselves out within a few seconds, which they almost never do, they'll go up in smoke. A vampire cannot enter a living person's home without an explicit verbal invitation from a resident, but once invited can return freely afterward until disinvited by an expensive and tedious ritual. They find crosses aversive and are scalded by holy water. I abstain from commenting on the theological implications."