Apex Rechargeable Princeton Tec Headlamp. This APEX has a rechargeable lithium ion battery pack for 90 hours of burn time. The battery pack clips to the headstrap or can be moved to the user’s belt or stashed in their pack with an extended power cable. A USB charging cable comes standard with the headlamp, making it easy to replenish the battery whether at home or overseas. With a single Regulated Maxbright LED partnered with four white regulated Ultrabright LEDs, the Apex provides either a powerful spot beam or a flood of light. With two big buttons switching between modes is easy even with gloves on.