Avalanche photodiode, an Uncommon card

The card carries these facts from its Wikipedia article.

• APDs use materials and a structure optimised for operating with high reverse bias voltage, approaching the reverse breakdown voltage, such that charge carriers generated by the photovoltaic effect are multiplied by an avalanche breakdown, thus they can be used to detect relatively small amounts of light.
• From a functional standpoint, they can be regarded as the semiconductor analog of photomultiplier tubes, unlike solar cells, they are not optimised for generating electricity from light but rather for detection of incoming photons.
• Typical applications for APDs are laser rangefinders, long-range fiber-optic telecommunication, positron emission tomography, and particle physics.

Rarity in WikiCards follows a year of Wikipedia page views: the most read articles become Epic and Legendary cards. The Avalanche photodiode article was read about 18,000 times in a year. ATK comes from the length of the article and DEF from its quality, so this card hits with 58 and blocks with 32: each hit it takes is cut by 13 %.

Open packs. Each pack holds five cards drawn from real Wikipedia articles, the rarest last, and the fifth card is always Rare or better. The odds are shown in the game. A free pack arrives every hour and two can wait, and the Coins you win in duels buy more packs.

The cards just above and just below Avalanche photodiode in the power ranking, all domains together.