The PENN Cool bags are made of a 500D polyestermaterial with PVC coating and the inside is made froma strong and high quality isolation material. As well,they are finished with a strong SW proof zipper withzipper pullers. The smaller size is perfect forstoring bait for shore sessions or bringing somedrinks, while the large size is perfect for longersessions, fitting a large amount of bait and even havespace for food and drinks. As well, it will fit traysof bait and it is ideal to carry fish home from theend of a session in prime condition.