I think as long as they're smooth and you don't pull your hair too tight, those are fine. FYI you can make them yourself by buying elastic by the yard at your sewing store!
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3b, fine, medium density, normal porosity
Wash: Deva No Poo, sometime Phytojoba, Avalon lemon when needs clarifying
Rinse-out: Deva One Condition, CJ Beauticurls Strengthening, Phytojoba (kinda heavy for my hair but good noisture)
DT: CJ CCCCL, or KCKT
Leave-in: Phytokeratine, CCCCL
Styling: Deva Coconut Supercream or their Wave Maker with a little CS over the top