Nylon/Poly Blend 
It has pockets!

LOW CUT BACK

Adjustable straps. You can make it shorter or longer
The model is wearing a small. She's 5'7 size 3/4
You can go down a size

Small fits up to 7/8
Medium 9/10-11/12
Large 13/14-14/16
XL 16/18-18/20