Nambala yogwiritsira ntchito patent: ZL201220705818.X

Nthiti ndi thupi lakunja zimapangidwa ndi mbale zachitsulo za 10mm, ndipo bwalo lamkati ndi cone zimapangidwa ndi zitsulo zazitsulo za 4mm Miyeso ya mkati ndi mkati mwa cone imapangidwa mwa kuwerengera molondola, zomwe zimakhala zomveka komanso zolondola ndi athunthu ndipo akhoza kupangidwa molingana ndi mikhalidwe yeniyeni.