The Fenix FD41 LED flashlight features a rotatable ring around the head which allows a user to adjust the focus between spotlight and floodlight. The flashlight measures 146mm in length with a head diameter of 40mm. The FD41 weighs 160 grams without batteries. The flashlight is housed inside an aerospace-grade aluminum casing which features a crenellated bezel and a Type III hard-anodized anti-abrasive finish. The flashlight also features knurling and a tactical grip ring.
The FD41 utilizes a Cree XP-L HI LED and an optical lens with total reflective coating. The flashlight can be powered by one rechargeable 18650 Li-ion battery or two CR123A Lithium batteries. Reverse polarity protection guards against incorrect battery insertion. The FD41 produces a maximum output of 900 lumens, a beam throw distance of 340 meters and five light modes: Turbo 900 Lumens 1Hr 40Min; High 350 Lumens 3Hr 50Min; Mid 150 Lumens 10Hr 15Min; Low 10 Lumens 150Hr; Strobe 900 Lumens. The light achieves the maximum output with the 18650 3.6V/3500mAH battery
The flashlight is operated by a tactical tail switch and a stainless steel side switch for output selection. The focusing ring around the head allows the user to adjust the beam. Press the tail switch partway down for momentary-on operation and all the way down for constant-on operation of the flashlight. With the FD41 turned on press the side switch to cycle through the various brightness levels. Rotating the ring with the light turned on moves the head and the optical lens forward and backward from the LED adjusting the focus between spotlight and floodlight.
The Fenix FD41 also features overheat protection which prevents the surface of the light from overheating. The flashlight is a quality lighting tool which would be especially useful for camping, caving, hiking, hunting and search and rescue. The FD41 pack includes a holster, lanyard, O-ring, rubber switch boot and user manual.