Electro-Caps are an EEG electrode application technique. They are made of an elastic spandex-type fabric with recessed, pure tin electrodes attached to the fabric. The electrodes on the standard caps are positioned to the International 10-20 method of electrode placement. The medium Electro-Cap will fit approximately 65% of all patients over the age of 5. The small cap will fit primarily children from the ages of 2 to 5 years. The extra small cap will fit most children from 9 months to 2 years of age. Sizes in age are approximate; the patient should always be measured to determine proper cap size.