Below is the seller's description. It does seem a tad small.

Caliber 471. Swiss made.
Serial number 15893859 (circa 1956).
Automatic winding (early & scarce "bumper" autowind)
Sweep second.
20 jewels; f = 19800 A/h
Stainless steel, ref. 2790-7 SC.
Some usual tiny scratches & nicks, more visible on back.
No buffing, 100% original patina, just ultrasonic cleaning.
Measures approx. 31.8 mm across, without the authentic, like new Ω crown.
38.5 mm tall lug to lug; 10.4 mm thick.
MEDIUM SIZE (roughly 1¼" wide, 1½" tall, 3/8" thick)

 

Seller is full of shit. That is no bumper movement. It is indeed medium sized if you have a womb.

 

Don't have a womb but now that doubts have been cast on the dial and seller, I'll move on to something else. Thanks guys.

 

It seems like you are pretty new to this and are learning (like myself). I concluded that there is a lot of overpriced, fake, and non-original watches on eBay. Yes, people find gems there, but those people have a lot more knowledge than I do. I would try estate sales, flea markets and the like. You can get your feet wet buying watches in the sub $100 range. It is all low stakes. I feel like you get a better understanding when you can lay hands on a watch.