NEW WITH TAGS -- THIS BLOUSE IS MARKED AS A SMALL BUT IT SHOULD BE MARKED AS A MEDIUM. I WEAR A LARGE AND IT IS ONLY SLIGHTLY SMALL ON ME. SO MEDIUM WOULD FIT BEST. LAYING “FLAT” THE UNDER-ARM MEASUREMENT IS 20 INCHES. THE REASON THIS BLOUSE IS A HIGHER PRICE IS THE WAY IT FEELS AS YOU WEAR IT. IT IS OF INCREDABLE QUALITY AND MADE IN THE USA. I WOULD WEAR THIS WITH WHITE BERMUDA SHORTS OR DRESS SLACKS. IT WOULD BE A KNOCKOUT. PAY ATTENTION TO THE MEASUREMENTS. IT COMES FROM A SMOKE AND ANIMAL FREE HOME AND I USUALLY SHIP THE FIRST DAY.