This soft line equals the following equivalent 1:1 size at each scale.
1/25 scale = 1/2"
1/16 scale = 1/4" or 5/16"
1/12 scale =1/4"
1/8 scale  = 1/8"

Typical uses are small oil, vacuum and fuel lines, especially fuel & nitrous delivery at the the carbs, manifold, injector plate or injectors.  
This soft rubber line is easy to bend and shape to your installation. 

Each package contains one coil of .020 x 18" rubber tubing