Iyunithi yokuqala ifana neyesibili. Uma ufaka amanzi, iyunithi ingasetshenziswa ukususa ufulawa wokunyathelisa. Iyunithi yesibili iyidizayini enama-roller amathathu, lapho i-roller yayo yerabha isebenzisa khona izinto ezithile ukuze ikwazi ukumboza umkhiqizo ngokulinganayo ngomphumela omuhle. Futhi ifanela uwoyela osekelwe emanzini/osekelwe ku-oyela kanye ne-varnish ye-blister, njll. Iyunithi ingalungiswa kalula ohlangothini olulodwa.