It is the eighth letter of the Samaritan alphabet and carries the numeral value eight. It stands where Hebrew has het, and it once wrote a strongly rasped h made at the back of the throat. It is the third of the four throat letters whose consonants have weakened in the Samaritan reading tradition, which is why the letter name is It rather than something beginning with that sound.
Like zen, this letter covers more than one sound of the ancestor language. Two distinct back consonants of the earlier Semitic system were both assigned to it when the twenty-two signs were fixed, and Arabic still writes them with two separate letters. The evidence that they were once distinct in Hebrew comes from outside the Hebrew script: Greek transcriptions of Hebrew names, made when the distinction was still audible, sometimes render the letter one way and sometimes another, and the split follows the older pattern rather than the spelling. That is a small but exact demonstration of something an alphabet cannot show about itself.
Greek took the sign as eta. In the earliest Greek use it stood for the h sound, close to its Semitic value, and only later became the long vowel it is in the classical alphabet. So a letter that writes a throat consonant in the Semitic scripts is a vowel in Greek by way of a sound that fell out of the language.
The character is encoded at U+0807.