The first three models (VM 130, VM230 and FOLD3) all belong to manual resistance adjustment type, while VM400 and VM530 belong to electromagnetic control automatic type. In terms of load-bearing, four models of products, VM 130, VM230, FOLD3 and VI400, can all bear 1 100 kg, while VM530 can bear up to 130KG. From the outside, the old people have bad legs and feet, and VM400 and VM530 are more comfortable.