I-Countersunk washers yokugqibela zii-boteners ezikhethekileyo ezenzelwe ukulungiselela intloko yesikrufu okanye ibhalt, ukuvumela ukugqibela. Ezi zihlaziyo zahlukile ngenxa yesimo sazo esincinci, esenza ukuba i-botener ihlale ngaphantsi kunomphezulu wezinto, ukudala imbonakalo egudileyo nobuhle. Olu uyilo luncedo ngokukodwa kwizicelo apho i-sleek kunye ne-pron