The X2 G2.1 is the perfect balance of weight and output making it light enough for helmet and bright enough for the bars. This kit includes the Power Pack 5, which is a 5,000mAH Li-ion external battery that is rated for 1.5 hours of runtime at max power, or 8 hours of runtime at 20% power. You can use this light as either a helmet light or a bar light, and we recommend adding the Gloworm Battery Cradle for mounting the battery to the frame. The Gloworm X2 G2.1 Light System is nearly identical, but has a larger 10,000mAH Li-ion battery pack that has double the runtime at the expense of an extra half pound. Upgraded models now have improved long term reliability as the USB-C port has been removed from both the light and battery and lights now feature dedicated external cables Provides 2000 lumens with the convenience of a wireless remote and mobile app customization Adventure model has a smaller power supply than standard model Lightset includes: X2 light head, remote, power cables, 31.8/35mm bar mount, Power Pack, and charging adapter cable TECH SPECS Model X2 G2.1 Adventure Lightset Headlight Lumens 2000 Modes 4 Rechargeable Yes Color Black Weight 456g table{border-collapse:collapse;width:100%;}td{text-align: left;padding: 8px;font-weight:350;}tr:nth-child(even){background-color:#f2f2f2}th{background-color:#eb212e;color:white;text-align:left;padding:8px;}.desc ul{font-size:24px;font-weight:600;margin-left:-25px;padding-top:35px;border-top:3px solid #f0f0f0;}.desc li{list-style:none;border-bottom:4px solid #eb212e;width:142px;}