Rid-O-Mice offers 2 sizes of covers.Most Common - 2.75 Inch Brick Height
Next Most Common - 2.25 Inch Brick Height
The larger size is 2.75 inches mainly for 2.75 inch brick which is quite common. However, these days, some brick is 3 inches in height so the 2.75 inch cover is a full 2.75 inches in height. This way it can be used in a 3 inch long hole. See here for more detail.
The 2.25 inch brick is another common size brick. Our cover for this size brick is 2 inches tall. The cover when centered in the 2.25 inch hole top and bottom leaves a small gap at the top and at the bottom similar to the spacing in the grill. This is the same as experienced when using the 2.75 inch weep grill inside the 3 inch hole. This method provides complete protection against mice and wasps, lizards, scorpions, snakes and large insects.