Have you ever heard of a belt that can help you get skinny? One that claims it can get you in shape? And what about the latest fitness craze — using Russian weights to get extra fit? Possible? Here's what we found in two of our latest investigations.

Slendertone Flex (www.slendertone.tv)

Claim: "Use your Flex Abdominal Toning Belt for just 30 minutes a day, five days a week, and in just weeks, your abs could be firmer, stronger and more toned. Satisfaction Guaranteed!"

Facts: The Food and Drug Administration regulates electrical muscle stimulators; however, most stimulators are intended for use in physical therapy and rehab. This is what the FDA Web site has to say about EMS products: "The FDA has cleared many electrical muscle stimulators for prescription use in treating medical conditions. Doctors may use electrical muscle stimulators for patients who require muscle re-education, relaxation of muscle spasms, increased range of motion, prevention of muscle atrophy, and for treating other medical conditions which usually result from a stroke, a serious injury, or major surgery. Again, the effect of using these devices is primarily to help a patient recover from impaired muscle function due to a medical condition, not to increase muscle size enough to affect appearance."

Yes, it is true that the Slendertone Flex has been "cleared by FDA for toning, strengthening and firming abdominal muscles."

According to Fabio Comana, an exercise physiologist for the American Council on Exercise, "Any time a group of muscles performs more work, it should offer some benefits. If this is used on very de-conditioned individuals with weak abdominals, the muscles will be stimulated to contract and will get stronger" as long as the muscle does more work than usual.

Fiction: The following is taken directly from the FDA Web site: "Using these devices alone will not give you 'six-pack' abs. Applying electrical current to muscles may cause muscles to contract. Stimulating muscles repeatedly with electricity may eventually result in muscles that are strengthened and toned to some extent but will not, based on currently available data, create a major change in your appearance without the addition of diet and regular exercise." Also, according to the FDA: "No EMS devices have been cleared at this time for weight loss, girth reduction, or for obtaining 'rock hard' abs."

The price: About $200.

Concerns: "Spot reduction is a myth, and people often confuse improved abdominal endurance and strength with getting a washboard stomach. We all have a washboard, but for most, it is covered with a layer of fat tissue that has to be shed in order to show the six-pack," says Comana.

Bottom line: If you want washboard abs, this belt will not do it for you. Try ab work, cardio and a healthy, calorie-lowering diet.

Russian Kettlebells

Claim: This cannonball with a suitcaselike handle is better than free weights for strength training, and kettlebells are the only workout you need.

Facts: Kettlebells can provide a challenging, effective workout for those who are bored with traditional free weights or simply looking for an alternative. The design of the kettlebell results in its center-of-mass being outside the grip because of the handle placement. This results in a far different — and greater — challenge than most free-weight exercises and can provide a terrific challenge to the muscles of the forearm, shoulder and core, says Jonathan Ross, a spokesman for the American Council on Exercise.

Kettlebells can help people strength-train and get them prepared for real-life situations.

"Kettlebell exercises help with regular everyday functions such as lifting groceries, carrying a pile of magazines, gardening, throwing out the trash or lifting a child — moving irregular-size objects and controlling the momentum," says Tedd Keating, a professor of physical education and human performance at Manhattan College.

"Kettlebells use a swinging, curvilinear pattern when performed, whereas free weights have a linear pattern. It's actually in the process of accelerating and decelerating the movement of the kettlebells that the strength and power gains are made," he adds.

A kettlebell is a compact and convenient piece of fitness equipment. All the exercises use one kettlebell, so once you find one the appropriate weight, you don't need an entire set to do your strength-training program. As you get stronger, you simply do additional reps and increase movement speed, says Keating.

Fiction: Kettlebells will provide you with a better workout than free weights. Actually, kettlebells are simply different from free weights, not necessarily better. "It provides a different, unique challenge to your muscular system," says Keating. This is not the be-all and end-all when it comes to fitness — it's just another tool in your fitness toolbox.

Price: $24.95 (10-pound) to $109.95 (100-pound)

Concerns: Kettlebells can be unexpectedly heavy, and since the design adds an additional "unwieldy" component, that can be both helpful and dangerous.

"Many of the movements with the kettlebells are done rapidly — thus generating a significant need to control the momentum of the weight," says Ross. Additionally, kettlebells can create an excessive challenge to the forearm muscles, putting the wrist at significantly greater risk of injury.

"The weight of the kettlebell is far outside the grip, thus dramatically increasing the torque on the wrist joint (imagine trying to swing a sledgehammer like a carpentry hammer). This property of the kettlebell — one of its most frequently stated attributes — needs to be respected and handled with care.

"A frequent mistake people make is to compare what it feels like to lift a 25-pound dumbbell overhead to lifting a 25-pound kettlebell. Given the different properties of the two, a far lighter kettlebell should be used," says Ross.

Bottom line: Kettlebells can be very effective if used appropriately and very dangerous if not.

Charles Stuart Platkin is a nutrition and public-health advocate, and author of "Breaking the FAT Pattern" (Plume, 2006). Sign up for the free Diet Detective newsletter at www.dietdetective.com.