I use this brand and like them except for the safety guard that is supposed to prevent you from clipping the quick. The only time I ever did cut into the quick was using the safety guard, so now I slide the guard out of my way. They've stayed sharp now for two years.
My vet just used human nail clippers when he first showed me how to cut Ruby's nails.
I also use a Peticure too smooth their nails after clipping.
J-B Wholesale Pet Supplies, Inc.