Some tubes doesn't print 3 sizes(1.75/1.95/2.125). Those are able to cross 1 size. It's supported 3 sizes.
"The tube is like a balloon"
Example :
1.75/1.95 >up 2.125
1.5/1.75 >up1.95
1.25/1.5 >up1.75
FKR AV BICYCLE INNER TUBE 16" 20" 24" 26" x 1.75/1.95/2.125 (Standard 28mm valve length)
Motor/Car/American Valve
It's one size fit all 1.75/1.95/2.125 tube.
-16x1.75/1.95/2.125 AV BICYCLE TUBE
-20x1.75/1.95/2.125 AV BICYCLE TUBE
-24x1.75/1.95/2.125 AV BICYCLE TUBE
-26x1.75/1.95/2.125 AV BICYCLE TUBE