? WHAT IS THE PRADER ORCHIDOMETERPrader Orchidometer is a medical instrument that can be used to accurately measure volume and determine the size of the testicle. The cutout sizes are compared with the testicle of the patient using the volume that matches most closely in size. In the absence of varicoceles, the right and left testes are approximately equal in size. Pre-pubertal sizes are 1-3 ml in yellow, pubertal sizes are considered 4 ml in orange and up and adult sizes are 12-25 ml in red. Doctors sometimes informally refer to them as "Prader's balls", "the medical worry beads", or the "endocrine rosary." ? WHY DO WE NEED AN ORCHIDOMETER TO MEASURETo provide a patient with a symmetrical, natural appearance in the scrotum, it is important to closely match the size of the existing testes. This can be accomplished by determining the size of the existing testes by using an Orchidometer. The Orchidometer is also an important tool for endocrinologist and pediatrician. ? PRADER ORCHIDOMETER USER?S INSTRUCTIONGently pull the scrotal tissue taut around the existing testes. Place the Prader Orchidometer over the testes to assess the size that most closely resembles the current testicular size.Pre-prepubertal is defined by Tanner Staging as a testicular volume less than 1.5 ml, however 4 ml is considered to be a clinical marker of the start of puberty in boys.