Mounted on your helmet or your handlebars, Fireballs Comp ($299) bicycle headlamps provide from 105 minutes to eight hours of light (depending on which of the four output levels you use). Made by Specialized, Fireballs are housed in an aluminum frame that weighs only nine ounces and are controlled with a wireless handlebar-mounted switch. Each halogen bulb sits in its own adjustable socket, allowing the beams to be aimed independently. A gauge inside the battery pack tells you when you're low on power. Specialized, 408-779-6229; www.specialized.com.
You no longer need a hiking partner to remind you that you don't know where you're going. The Outback digital compass ($79.99) has lights that indicate anytime you deviate from the proper azimuth. Made by Brunton, of Riverton, Wyo., the Outback has up to 200 hours of battery life and can be programmed to store multiple routes to, and from, your favorite fishin' holes. Brunton, 800-443-4871; www.brunton.com.
Although it resembles an accessory for 007 in Thunderball, the Dolphin ($895) is purely recreational. Made by SeaScooters.com of Pompano Beach, Fla., it is a handheld device that propels swimmers underwater and is ideal for scuba diving and snorkeling. The Dolphin runs for about an hour on a rechargeable battery. Its maximum speed is only 3.2 miles per hour, but it can descend to depths of 130 feet. SeaScooters.com, 800-226-0767; www.seascooters.com.
If tennis elbow is your problem, the Abzorber ball ($3.99 per can) is designed to ease your pain. It is slightly lighter and firmer than normal tennis balls, and its manufacturer, Dunlop Sport, of Greenville, S.C., claims that the Abzorber reduces impact on the racket arm. Dunlop, 800-277-8000; www.dunlopsports.com.