heavy duty truck spring 1.material: 60Si2Mn(SUP6) 2. ... 1) type: straight leaf spring, z type leaf spring, multi leaf spring , return spring, brake spring, adjuster spring etc.2) Material: SUP6 ... or according to your requirements5)high quality leaf spring with competitive price;6) Certification: ISO 9001 ... like to develop new leaf spring according to your special requirement. heavy duty truck spring