Open Cover是指“预约保险单”，又称“开口保单”、“敞口保单”，是保险公司承保被保险人在一定时期内发运的，以CIF价格条件成交的出口货物或以FOB CFR价格条件进口货物的保险单。预约保险单载明保险货物的范围、承保险别、保险费率、每批运输货物的最高保险金额以及保险费的计算办法。如Where Party A fails to perform the obligation of paying premium in accordance with this Open Cover, Party B is entitled to refuse to make compensation or make compensation in the proportion of the actually collected premium to the premium to be collected upon occurrence of insurance accident.

甲方如果未按照预约保险单履行支付保险费义务，出险后乙方有权拒赔，或按实际保费与应收保费之比例赔偿。