their are tons of these on the market, mainly use tinks or the urine from a doe or buck i've killed.cover scent are good,or you'll get busted,use something natural, or that will make them curious,as far as using doe estrus scent, be careful. big boy has been known to attack.use those bombers like little magum described, i use a drag when using the estrus scent. has worked pretty good in the past.