Welch Allyn 3.5V Lithium Ion Handle, Charger and Transformer • Smaller diameter and half the weight of full-size 3.5V NiCad handles • 120 minutes of operation between charges (compared to 60 minutes for standard Nicad handles) • Also charges in Universal Desk Charger • Compatible with all Welch Allyn 3.5V instrument heads • Low battery indicator light.