Presidium Gem Tester II (PGT II) Includes: GemTester II, Probe Pen, AC Adapter, User Handbook, Warranty Registration Card, Case Built-in Calibration (CAL) and Glass Test Discs Probe Pen with a Retractable Thermoelectric Tip isthe industry's thinnest at 0.6mm for testing diamonds as small as 0.02 ct Enclosed AC Adapter or you may use 2 AA Batteries for on the go