N/B Medium and XL is the dark brown cap, while the Large size is the light brown cap

Light Brown picture is the Large size cap

Brown picture is the Medium and XL caps 

This cap is for making a full lace glueless wig. Has adjustable strap at the back.

If you can ventilate, then you will ventilate the whole cap but if you can’t ventilate, then you can attach wefts to the whole caps and either place your closure on top or ventilate the lace on top