No dexterity or skill needed; just pull the knife through the slot
Doesn’t every kitchen have one in a drawer?
I must have got a bad one – it just gouged up the cutting edge on the knife. The knife did “feel” sharper, but the edge generated looked awful & didn’t last long.
Just use a Lidl diamond coated round sharpener now & “guesstimate” the angles. Puts a decent edge on that lasts well. Lidl get them in every now and again at under £5 – includes a collet closing handle & the coated rod slips inside the handle when not in use.
Nigel B.