The internal battery is not huge. I typically get a weekend's worth of use on an overnight backpack trip, so figure about 4 hours of relatively low duty cycle. Maybe 20% or so TX to RX. For a week long trip I bring along a solar panel and maybe a small battery pack.
It's a 5W all mode, so on VHF and UHF FM it's like an HT. On higher efficiency modes on VHF and UHF it's all about height over terrain. On a mountain top it's 75 or 100 miles simplex and with a yagi you can sometimes hit the state's high points.
On HF it's all about the antenna, propagation and conditions. It'll do local 40m NVIS as well as any other rig, e.g. pretty reliably get most anyone in CO/WY/NE/KS/UT/NM. On DX bands 5W QRP can be challenging, but digital modes (Morse, RTTY, JT65) I've been able to as far as Australia, AK and a few distant corners of the lower 48. On phone (SSB) figure with regular conditions a few hundred miles is possible.
Remember this is a very small QRP radio that operates HF up to UHF. It covers 160m, 80/75m, 60m, 40m, 30m, 20m, 17m, 15m, 12m, 10m, 6m, 2m, 70cm on AM, LSB, USB, FM and CW. It also receives broadcast AM and FM and all the SW bands in between our ham bands as well can receive CB. Thing is about the size of a large paperback book.
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"Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty. Nobody is able to achieve this completely, but the striving for such achievement is in itself a part of the liberation and a foundation for inner security. " --Albert Einstein