Pickled Okra

From Epicurious.
Ingredients:
1 pound okra (3 1/2 to 4 inches long)
6 garlic cloves, peeled
3 cups cider vinegar
1 cup water
1/2 teaspoon dried hot red pepper flakes
1/2 tablespoon dill seed
1 tablespoon mustard seeds
1 1/2 tablespoons kosher salt
1 tablespoon sugar

Sterilize jars and lids: Wash jars, screw bands, and lids in hot, soapy water, then rinse well. Dry screw bands. Put jars on a rack in a boiling-water canner or a deep 8- to 10-quart pot and add enough hot water to cover by 2 inches. Bring to a boil, covered with lid, and boil 10 minutes. Heat lids in water to cover in a small saucepan until thermometer registers 180°F (do not let boil). Keep jars and lids submerged in hot water, covered, until ready to use.
Make pickled okra: Drain jars upside down on a clean kitchen towel 1 minute. Tightly pack jars with okra, stem ends up, then put 1 garlic clove in each jar. Bring remaining ingredients to a boil in a 2-quart nonreactive saucepan, stirring until sugar and salt are dissolved. Divide pickling liquid evenly among jars, leaving 1/4-inch space at top, then run a thin knife between okra and jar.
Seal and process jars: Wipe off rims of filled jars with a clean damp kitchen towel, then firmly screw on lids with screw bands. Put sealed jars on rack in canner or pot and add enough hot water to cover by 2 inches. Bring to a boil, covered. Boil pickles, covered, 10 minutes, then transfer jars with tongs to a towel-lined surface to cool. Jars will seal (if you hear a ping, that signals that the vacuum formed at the top has made the lid concave).
After jars have cooled 12 to 24 hours, press center of each lid to check that it's concave, then remove screw band and try to lift lid with your fingertips. If you can't, the lid has a good seal.
Let pickled okra stand in jars at least 1 day for flavors to develop.
Makes 6 half pint jars.