What type of rods are used in a perm for a wave pattern close to the head?

Concave rods are specifically designed to create a wave pattern that is closer to the head. Their unique shape allows for tighter curls at the center while gradually softening towards the ends, resulting in waves that follow the natural contour of the head. This creates a more blended and natural look in the finished perm style, enhancing the overall appearance of the hair while achieving the desired wave pattern.

In contrast, straight rods are typically used for uniform curls without any variation in wave size, which would not achieve the same effect close to the head. Spiral rods are typically used for spiral or corkscrew curls and might create a different look than what is desired. Flexi rods can provide flexibility in styling but are generally used for looser curls rather than structured wave patterns close to the scalp.