PKG(2) Quartz Crystal Antennas. Made to Be Used in Pairs as Part of a 300 Ohm Antenna. Build your own quartz antenna. These (2) 4-3/8" x 3" x 1-5/16" plastic boxes each have (2) boxes of quartz crystals inside and (2) aluminum U-brackets that are attached to a single screw terminal on one short side of the box. They're made to be used in pairs as part of a 300 Ohm antenna. All you need is cabling to connect them. Made in Brazil, the antenna capital of South America, probably.