The lamp is all metal with a nice black paint. It could almost be a baton ... lol Length 24cm (2 items) plus an extension of 7cm (one item). I chose the TrustFire 26650 3.7V 5000 mA. (68mm long x 27mm diameter). In the box we find the adapters (plastic sleeves) to use 18650 (68mm long x 18mm diameter). The light output is at the rendezvous, a walk in the night, all lights around you, like a car headlight. I tested the most powerful fashion over 1 h, careful, very hot lamp is burning limit, but was raised and its nylon sheath (which is different from the picture but more functional). We understand better the presence of all the fins and ridges around the head. Additional Information: with 18650, I can not operate the strobe function and SOS, there is a slight transverse play between the batteries and the sleeve which produces noise when the lamp is moving or shaking. 5000mA Battery 2x26650 performed with the same seller: 1:30 at full power. / Average position 2H / over 7H minimum position