Bref Toilet block Perfume Switch peach & apple allows you to place two types of fragrance in the toilet block. The primary odor is only released when the toilet block is dry. The secondary odor begins to release with each flush. After the toilet block has dried, the primary fragrance starts to be released from the block again.aBref Toilet block Color Aktiv with the scent of fresh flowers will leave your toilet hygienically clean and fresh with each flush thanks to the active substances contained in the blue water. In addition, the Bref rigid toilet block Color Aktiv effectively fights scale.