i am a firm believer in them. 2 companies seem to make them. i have used both and only seem to get result from the comany that makes them in the black can (cant remember which compant makes it). as for how long it lasts, it seems that the scent sticks to everything and lingers for SEVERAL hours. that being said...try not to get it on your hands. i set one off in the morning and can still faintly smell it on limbs i have sprayed until the early afternoon at which time i set off another just as a "recharge", although i probably don't really have to. also, the claim to work up to 1/8 of a mile when set off on the ground. however, my hunting parter says that he set his off on the roof of his deer stand to get that little extra distance. he and i combined probably used 8 cans last year, and only had one semi defective....that is that the can only released havf its contents. but when he called the company, they gave him a voucher for another can. so all in all, VERY well worth the shot. i shot one doe and one 7 point using it. and he got a 6 point. keep in mind, with any lure and call, it will not bring you in a deer EVERY time.