Genuine Honda front fork cover rubber. On the early style forks from the 60's into the early 70's with the painted fork covers, there are 2 rubber parts between the upper and lower fork covers. This is one of the rubber parts, the other is a rubber guide (Honda Part Number: 51623-292-670). On the later style forks, this rubber part goes between the chrome fork rib and the chrome fork cover. Check your model to make sure this is the part you need.
Honda part number: 51622-292-010
CB450K - 1968-1974 (1968 VIN# CB450-3000001 TO CB450-3008955)
CL450K - 1968-1974
CB550F Super Sport - 1977 - VIN# CB550F-2100001 TO CB550F-2114871
CB550K - 1977 - VIN# CB550K-2000007 TO CB550K-2015308
CB750K - 1969-1977 (1977 VIN# CB750-2700009 TO CB750-2729534)
may fit other models...