how do you determine size so it will fit

As someone posted, go by the shirt size. So XL would be around 46-48 shirt size. XXL would be 50-52 shirt size. I will be honest. I ordered the product and it did not fit right. It did not give support to my left shoulder. I have this product and it works much better: http://www.amazon.com/EVS-Sports-Shoulder-Brace-Medium/dp/B005MJYTYC/ref=pd_sim_sg_2?ie=UTF8&refRID=0VG5Y8TFV9E5V4HC3GAD

My opinion and from putting my own on just to verify , I would say that it is a harness meant for the right shoulder. My own personal one is meant for the left shoulder and is completely opposite of this one. Dennis

On you're chart you show a 3xxl is one available? I dont see one

Hello and thank you for your inquiry into our Shock Doctor Shoulder Support. The Support is available in a XXL and XXXL option but at the moment both are sold out. I do apologize for this and if you have any further questions regarding this or any of our other products please feel free to contact our customer service department through Amazon Messenger.

For the X-fit strap that velcros onto the shoulder, sliding them into which of the 3 notches gives the best support (top, middle, or bottom) ?

Once you have it on it really depends on the comfort level of support for you or for the individual. You won't know until you wear and make the proper comfort adjustment. Every body and person is different. Just keep adjusting the Velcro position until you feel the comfort and get good snug comfort .

Age Range	Adult
Color	Black
Size	L-XL
Style	Support
Shape	Wedge
Material Type	Plastic
Number of Items	1
Features	Adjustable
Usage	Shoulder Support,Muscle
Sport	Walking
Batteries Included?	No
Brand	Shock Doctor
Department	Unisex-Adult
Manufacturer	Shock Doctor
Item model number	83842
Product Dimensions	2.4 x 12.6 x 5.7 cm; 400 g
ASIN	B00598YBTO

Shoulder Brace for Men, Shoulder Support Brace, Prevents & Promotes Healing from AC Sprains, Rotator Cuff Shoulder Brace & Moderate Separations, Rotator Cuff Support Brace

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