This youth life vest by X2O is perfect for children weighing between 50-90lbs and with a chest size of 26-29". 
The vest is designed with safety in mind and is UCG approved. 
It comes in a beautiful blue color and is made by Exxel Outdoors, a trusted brand in outdoor products.

X2O Universal Youth Open-Sided Life Vest and Jacket, 50lbs - 90lbs, Blue Ocean Coral:

U.S. Coast Guard Type III approved flotation device
Quick-release buckles to make quick work of putting on and taking off this life vest
One-inch Webbing
Two adjustable body belts and an adjustable inseam strap ensure a secure fit 
Open-sided design
Ideal for children weighing between 30 pounds to 50 pounds
Unisex
Blue in color
100% Polyester Oxford Fabric
Fun silkscreen graphics provide a unique design
One-year limited warranty
SAFETY NOTE: A vest should be snug and not rise to impede vision/ hearing when arms are raised. 
Please make sure to try on vests before every outing to make sure they are in good condition. 
And as always, follow state boating laws while being out on the water.

All dimensions were done with jacket laying flat on table, and on one side only. 
So if you need to know more exact measurements times the length & width by two.
Dimensions: 17" Height x 16 1/2" Length x 9" (Adjust to 11 1/2") Width.
Features: High Viz, Tear Resistant.
Material: Polyester.
Country/Region of Manufacture: United States.