Peshutim Mehudarim (Superior Simple Ones) teffilin have boxes made from a single strip of hide as required, and the boxes are 35mm X 35 mm on each side. Goat skin is used to form lighter weight batim. When finished these look almost identical to the more expensive and more durable cowhide tefillin.
These Tefillin come with batim covers.

The Batim of these Tefillin are 35 mm, as pictured. Certified kosher and correct after proofreading by a qualified expert.
Each set is accompanied by a computer check certificate and a certificate of the kashruth level. Professionally made by "Peer Hastam".

Many people find these tefillin an ideal Bar Mitzvah gift.

Nusach Ktav Ari or Beis Yossef:
Here are some universal guidelines showing which communities traditionally use each ktav:
Ashkenaz Beis Yossef - is usually used by those adhering to the Ashkenazi tradition, originating in Germany, England, Russia and Lithuania.
Ashkenaz Ari, Ari Zal (Nusach Sefard) - generally used by those following the Hassidic Sefard tradition from Eastern Europe, including Poland, Galicia, Hungary, Romania and Slovakia.

Hand Strap Wrapping Direction:
Counterclockwise - Beit Yossef, Most Ashkenazim wear the knot to be tightened (not to be confused with the knot on the base which is permenently tied and always worn on the inside, facing the heart) on the inside and wrap inward.
Clockwise - Ari (Nusach Sephard) Ashkenazim and all Sephardim wear it on the outside and wrap outward.