Context:I am a adult male, 5' 10", ~175lb, with about 10% body fat. I've been tracking my physical measurements for about five years now, just to keep tabs on things. Since I have low body fat and high muscle mass, BMI isn't a great indicator of healthiness, so instead I've been using the Navy body fat formula -- BF% = 86.010 x log10 (waist - neck) - 70.041 x log10 (height) + 36.76 -- for measurements in inches, or -- %BF = 495 / ( 1.0324 - 0.19077 * log10( waist - neck ) + 0.15456 * log10( height ) ) - 450 -- for centimeters. This has given me consistent and what seem to be reliable results, +/- 3%, but it is sensitive to small changes in measurement (i.e. 1/8" variance is equal to about 0.3% BF) and I wanted to test the outcome against a second method to see if they were accurate in addition to being precise.Use:The Accu-Measure Fitness 3000 calipers are easy to use; they have a simple, functional design which will work for most people. The way it works is that the calipers have a slider, which you reset before the measurement. When you take the measurement, you squeeze the caliper together - thus pushing the slide along its rail - until the tab of the little arm clicks into its socket. When you release the pressure, the caliper returns to its open state, but the slide stays put, and you can read the measurement off the rail. All the calipers do is measure the thickness of the skin-fold inserted between the caliper pads, in millimeters. An included chart allows you use that measurement to estimate your body fat %. You can take one measurement - at the suprailliac (supra-illiac) right above the hip-bone, or four from the suprailliac, abdomen, triceps, and thigh, or even more, and use a calculator online to determine body fat % from that. You should probably take the measurement before any exercise or meals, to reduce the possibility of interference from transient factors.Review:I found the calipers very easy to use, though it is still tough to take some measurements without a partner. The suprailliac is easy, as is the abdomen and the thigh, but the triceps is tricky, as is the subscapular measurement on the back. Also, while this is still usable for someone with my body fat content, it's already a little marginal. Taking one suprailliac measurement returned a bf% of 11%, but taking four returned 8%, and a different four returned 5%, which is definitely wrong. So you need to take a few measurements and average them out. If you watch a couple videos on the subject, you'll understand how it works very quickly. The slider/rail system, paired with the click-arm, means you can get consistent results and takes a lot of the guess work out of use.So I think I'd recommend this for general BF% tracking, maybe in conjunction with the Navy formula, which is easier to calculate for oneself.Pros: super duper easy to use. Just pinch the side of your stomach and squeeze the caliper until it clicks.Cons: I don't think this is very accurate or precise. I get a different measurement depending on where I pinch and I don't know if the reading is right either.The AccuMeasure MyoTape MT05 and AM-3000 Fitness 3000 Personal Body Fat Tester Kit is really a long way of saying, "pinch-test calipers, easy-to-use measuring tape, and a sheet of instructions." The advantage to the tool is that it easily and accurately performs the fat pinch test. The MyoTape makes it really easy to measure your body without help: wrap the tape around your waist, arm or leg, click it into the socket on the handle, and when you press the button it will retract to where you can take a good accurate measurement.The calipers are for the 'pinch' part: instructions explain how to use one hand to pull fat away from your abdomen and hold it while you 'click' the calipers. Unfortunately, the 'click' doesn't hold the measurement--it's just an indicator that you've pressed hard enough--you want to read the calipers before attempting to pull them away. The instructions suggest the opposite and this is confusing. Your measurement needs to be a two-handed job: lift the skin/fat away from the body with one hand and put the calipers on the pinched area with another. With your thumb on the lever that you see in the picture, the 'click' noise means you've pinched correctly and should read the measurement at that point.The disadvantage to the tool is that the enclosed card focuses solely on the waistline pinch test: it tells you to take the measure just above the hip bone on the right-hand side (this is called "the Subprailiac pinch"). The enclosed chart gives you a body-fat measurement based on your age and this one measurement alone.If you really want to use these tools to properly assess your body fat, I will add information for you in the comments to help you get the most out of the tool. I took the multi-point measurements, plugged it into a simple website calculator, and got a precise answer of "18.3%". This worked much better for me than the ballpark number I get from the enclosed card and one measurement.For this Accumeasure bundle, it's not a bad choice. The price is really cheap for what you get, and that makes this a good deal. I still suggest using multi-point measurements and a website to run the numbers in order to have a more accurate assessment of your body fat. I'll include details for you in the comments below.