Key of G Products, Inc., offers to sell to Harmony Company one hundred MP3 players at $50 a piece, subject to certain specific delivery dates. Harmony replies with a signed purchase order that reads, Accept your offer for 100 I-appliances at $50 each. Must be delivered to our warehouse. Key of G does not respond or deliver the goods.

Please help explain the meaning " subject to certain specific delivery dates ". Is that mean they will make the delivery, but the delivery date is based on their provided?