Inner Tube, 622-630 mm x 20 mm thru 25 mm width.

(These tubes might be marked 18 to 23mm)

The 20-25mm tube size fits 622 mm rims wit 700c x 20-25mm tires as well as 630 mm rims with 27" x 1-1/8" or narrower tires.

Since tubes are stretchy, they do not need to exactly match the size of the tire.

Available in Presta or Schrader valve.