Park Tool CB-4 Bio Chain Brite. Park Tool CB-4 is a 100% biodegradable natural plant-based degreaser formulated for use in the CM-5.3 Cyclone Chain Scrubber CM-25 Professional Chain Scrubber or with a scrubbing brush as a general purpose degreaser. When used with a chain cleaner CB-4 gets bicycle chains clean inside and out so theyre good as new. Will not harm alloy plastic rubber or carbon fiber parts so its safe to use for cleaning cassettes chainrings pulleys or any other component that accumulates muck and grime.Use CB-4 full strength do not dilute with water. Cover parts in solvent and scrub using a brushWont harm alloy plastic or rubber parts table{border-collapse:collapse;width:100%;}td{text-align: left;padding: 8px;font-weight:350;}tr:nth-child(even){background-color:#f2f2f2}th{bac