The OB-19 Ol' Betsy Double Reed Mallard Duck Call. The OB-19 Ol' Betsy Double Reed Mallard Duck Call is a double reed mallard duck call by a special request from a customer that wanted her flag on a call. It is tuned to be blown easy and soft but yet stand up to an aggressive calling style so as not to lock up on you. Here at Haydel?s we are keeping the American tradition alive by listening to our customers. God Bless the USA!