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.
|Schrader (regular automotive) Valve||TU6778|
|Presta Valve (narrow type)||TU6878|
|Presta 48mm X-Long Valve||TU6880||TUA715|