The white represents Ein Sof - the Infinite Light - that is received by the Ten Sefirot of the Kabbalah:

Keter-Crown,
Chochmah-Wisdom,
Binah-Understanding,
Chesed-Lovingkindness,
Gevurah-Strength,
Tiferet-Beauty,
Netzach-Eternity,
Hod-Majesty,
Yesod-Foundation
and Malchut-Kingship.

Size - 12 x 17 cm (5 x 7 inches) Price - $2.00 per card (includes postage & handling) Also available as a small poster