qnli question: What was Metrolite and Sav-o-flex materials primarily used for? sentence: Later, Decca Records introduced vinyl Deccalite 78s, while other record companies came up with vinyl concoctions such as Metrolite, Merco Plastic and Sav-o-flex, but these were mainly used to produce "unbreakable" children's records and special thin vinyl DJ pressings for shipment to radio stations.