Ok , I be no expert and that be probably not entirely true , but as a relatively fit woman who do not think the 2-pound version for woman would be sufficient since I use a 5-pound hand weight normally , I be wrong to think the Shakeweight for Men would be the same as my handweight . after about 30 seconds I feel like I be gonna break something I might need someday . it might be appropriate for woman with significant upper arm strength , but then if she be already that fit she be probably already figure out what work for she . I be no couch potato , but it be definitely not a fitness aid I be even capable of use at this point . maybe I 'll be able to work up to use it , but I be not hold my breath . luckily I have a boyfriend and he think it be dandy , hence the four star . after pay attention to he usage it be novel enough to motivate he to work out , and he seem to sort of pick it up during commercial break for short session that seem to make he feel physically productive . he have not be use it long enough for I to say it be a undisputed success , but it make I feel less guilty about make the purchase , and he say he get a decent burn from use it . probably ok for man , NOT for woman with low-intermediate fitness level .