Assuming the pistol is the one pictured, the standard magazine capacity is 10 rounds according to the Walther web site. The only magazine listed is 10 round.
However, several other sites are listing the gun as having a 7 round magazine. That being the case, I would suggest you call the people you ordered from. My
guess is, the capacity listing in the ad is actually for the Walther PPK/S 380. Call to make sure.
I noticed that the ad claims the frame is made of stainless steel. If that is correct, then this is a major upgrade to the design. The original Umarex Walther
was made from a Zinc alloy. So was the slide. If this has changed, the information should be all over the web - and it is not. The pistol is manufactured
in Germany by Umarex. It has some internal and many external similarities to the original PPK/S pistols but is not the same gun.
Manufacture of the originals started in 1968. These pistols were made of steel and are out of production. No 22 caliber PPK, PPK/S or PP pistols have been
manufactured in the USA.