Adorox Clear Petal Style and Ridge Style Rubber Earring Replacement Backs Combo Pack (Clear (500 Pieces)) Each Package comes with 500 rubber earring replacement backs. Measures approximately: 2.0 - 2.5 mm. Comes in an assortment of petal and ridge style earring backs. Made of soft plastic, more comfortable than metal earring backs! Never worry about losing those earring backs again!