The BraiNet Placement Cap is designed for fast, accurate, and easy setup. The BraiNet template eliminates the need to measure and mark electrode positions. It is accurate, based on the 10/20 method of electrode placement, and ensures consistent, symmetrical electrode placement every time. No need to measure and mark electrode locations. Color-coded template with 21 scalp electrode placement locations. Designed to aid in rapid, accurate placement of full 10/20 system of scalp electrode placement. Sizing: 10/20 placement cap sizes are based on the circumference of the head from Fpz to Oz. Extra Small - 45.5 - 49 cm - Available Upon Request Small - 49 - 54 cm Medium - 54.5 - 57 cm Large - 57.5 - 62 cm *Electrodes and electrode lead wires not included.