Isabel you can go to any hardware store and get these . They are meant for Concrete, Solid brick, Solis sand-lime brick, Hollow block made from lightweight concrete, Multilayer composite concrete wall as well as Natural stone with dense structure, Solid block made from lightweight concrete & Solid panel made from gypsum.

They will work perfectly and they are much easier to use. You drill a hole the same size as your fischer and push the fischer into the hole then screw the screw into the fischer. Simple as that. Not much fuss at all.