The Leland ESL I (Emergency Strobe Light) is the perfect outdoor and adventure survival tool. This very trusted, and long time tested Survival Strobe, uses a simple D Cell Battery to produce night and day piercing flashes at a rate of 50 to 60 per minute for 10 plus hours. After that, the rate will slowly decrease. In fact, our tests showed the Leland ESL I to produce bright flashes past 40 hours! These US Coast Guard Approved Emergency Signal Strobe Lights utilize a simple XENON Strobe Module which produces a powerful flash of light which can be seen miles away. It all starts with the ESL I Signal Strobe's compact electronics package in which a capacitor pulls the energy from the battery and readies it to send it to the gas filled XENON bulb. The ESL I Signal Strobe Light will instantly mark your location up to three miles away! In our own tests, the Leland Emergency Strobe Light surpassed other emergency strobe lights of the same class. Because it is USCG Approved, durable and waterproof, the ESL I Strobe Light will be there when you need it. Be sure to look at our recreational strobe light combination, the ESL II (Emergency Strobe Light Flashlight). Leland Emergency Strobe Light Features: - Switch is easily operated while wearing gloves or in bad weather. - USCG Approved strobe is visible up to (3) miles at night. (USCG approved with included clear lens) - Operates up to 10 hours at 50 to 60 flashes per minute, then at a reduced rate for almost two days! - Uses one D-Cell Battery, available almost anywhere. - Approximately 4 1/4" long by 2 1/4" wide - Weight: 8 oz including battery (sold separately) - Strong ABS Plastic Body with durable attach point - Offered in three case colors: yellow, red and orange The Leland ESL I Emergency Strobe Light has been used by professionals for years. It has proven itself time and again. If you are looking for an inexpensive yet life saving and dependable strobe light, the ESL I is the way to go.