Below is details for medical adjust aluminum crutches:

Size:L/M/S 

packing: 10 pairs/carton 

A,High quality aluminum tube with aluminum alloy treatment on surface;
B,Reinforced central vertical tube provides better support force;

C,Specially designed expansion tube provides more convenience for adjustment;
D,There's rubber tube inside so as to prevent from friction of metal tube.
E,Anti-skidding rubber feet-pad with metal gasket inside makes it more durable;