The logo - 21cm. Real Eyes V2 logo is a distressed design, which means it is purposely designed to look like it's been through the wash a few times and is not 100% perfect.
The model in this photo is wearing a size L - print may appear smaller on larger sizes.
 
I am a ladies size 14
My bust measures 103cm, waist 89cm and hips 111cm. I wear a unisex L which is comfortable and roomy - that "boyfriend" look. If i wear a size 14 v-neck it is quite fitted around the belly, so i choose to wear a size 16 v-neck instead.