The F. Grill went into full use in March of 1868, completely replacing the Z. Grill. Of all the grills, the F. Grill was produced on the most denominations. The F. grill is 11 to 12 points in width by 15 to 17 points in height. A total estimated 291,590,000 stamps with the F. Grill of the 1-cent through 90-cent denominations of the 1861-1866 Issues were printed by the National Bank Note Company.