It has three pockets, a left, a right, and a HUGE middle that I fill with stray balls, towels, extra shirts, whatever... Anyways, one of the pockets is just normal black vinyl, but the OTHER pocket is lined in some type of reflective material. Any idea why? That's the pocket I keep my racquets in. I figure it might have something to do with an insulative property to keep my strings daisy fresh? I dunno. HALP TALK TENNIS. HALP.