I.Selelekela:
Sehlahisoa se na le mehlala ea sampole le litlhaloso tse leshome tse fapaneng tsa poleiti ea setsi, e loketseng (0.1 ~ 0.58) ho tloaela ho teba ka mokhoa o fapaneng oa mohlala. E sebelisoang haholo ka har'a lipampiri, ho paka le ho lekola sehlahisoa sa thepa ea boleng le ho lekola lintlha le mafapha. Ke sesebelisoa se ikhethileng sa ho leka ho etsa lethathamo la matla a khopiso le pampiri.
U No.1 0,100-0.140 MM
u No.2 0,141-0.170 mm
u No.3 0,171-0.200 mm
u No.4 0,201-0.230 mm
u No.5 0 0,231-0.280 mm
u No.6 0,281-0.320 mm
u No.7 0.321-0.370 MM
U No.8 0,371-0.420 mm
U No.9 0,421-0.500 mm
u No.10 0 0,501-0.580 mm