Threadbar Bolt yomwe imagwiritsidwa ntchito padenga lozikika kapena lotchingidwa ndi nthiti ndi nthiti, yokhala ndi nthiti pamwamba pake, bolt ya ulusi imatha kupereka kusakanikirana kwa utomoni ndi kusamutsa katundu.Amagwiritsidwanso ntchito kwambiri pothandizira pansi pantchito zamigodi, ngalande ndi malo otsetsereka