"It does not tell you on here, what the correct size bit to use is. The previous review again say's they work as long as you use the correct size, but again fails to inform what size that is !!!! Not very helpful at all."
"There is no doubt this product saves time. So long as you use the correct size masonry drill you will get a good fixing which, so far, seems reliable. However, beware that the twist shear strength of these screws is not good.
Make sure you drill a hole at least 1.5 cm longer than the screw. After drilling masonry/brick make sure you clear masonry/brick dust from the hole. If you don't carry out these points the screw is likely to block and jam and in most cases the head breaks off just at the threaded point. You are then left with re-drilling at a new position."