The 10-Watt Tektite 3500XL Expedition Strobe features a shock-resistant housing machined from a solid bar of aircraft aluminum plus a LEXAN® cap, is double O-ring sealed, depth rated to { 2500 ft | 770 m }, will run 100 hours on a set of three C-cell batteries. The 3500XL includes two eVDS factory programmed modes: a steady on mode for use as an emergency backup or area light plus the flashing on/off strobe mode. Visible at the surface for several miles/kilometers at night, the initial 1000 Lumen flash rate is 120 flashes per minute with fresh alkaline batteries. The 3500 XL has twist on switch with non-slip grip, aluminum black color body with sturdy attachment point for snap or lanyard. At { 9.2 in | 23 cm } long and { 2.2 in | 5.6 cm } wide this strobe is too big to fit in most pockets. Includes an adjustable wrist lanyard, and also includes a limited LIFETIME Warranty from TekTite.