支付条款在函电中的拟定 — 国际贸易填空题

某出口公司与英国买方签订一批运动器材出口合同，金额USD 60,000，支付方式为：买方在合同签订后10天内以电汇（T/T）预付合同金额的25%作为定金，余款采用不可撤销即期信用证（irrevocable sight L/C）支付，信用证须在装运期（6月15日）前25天开抵卖方。请补全函电中支付条款的英文表述："The Buyers shall pay 25% of the contract value, i.e. USD ____, by T/T within 10 days after signing the contract, and the remaining 75% by an irrevocable sight L/C, which must reach the Sellers no later than ____."