The difference between parfum and EdP is a slightly lower perfume concentration. 50 ml is a small packaging, but that also means you can take it in your carry-on when traveling.
From eBay
Ellen tracy by ellen tracy eau de parfum spray 1.7 oz / e 50 ml [women]
Parfum France
Ellen Tracy Eau De Parfum Spray Women 50 ml
OnBuy
ELLEN TRACY by Ellen Tracy Eau De Parfum Spray 1.7 oz