I can’t be 100% certain of authenticity because I bought this top online. I paid a good price for it in a sale but I’m just reiterating that I can’t be 100% certain because I didn’t buy from the brand retailer or a popular designer shop therefore this is reflected in the price. The top is in very good condition and is a lovely material with a bit of stretch in the fabric. The reflective strip across the front has slight signs of wear from being washed. Size is a XXL but it fits like an XL.