Manufacturer: American Standard Tank P/N: 4192B Rough-In: 10" 3" Flush Valve  Tank Only, does not include lid or internal parts. Internal parts and Lid 3-740 Can be purchased separately Note that this tank uses the lid 3-740, which is also used on Crane 3740 tanks. However, the tanks are not interchangable. This tank has a 6.5" bolt spread, and the Crane 3742 tank has a 5.5" bolt spread. If you are identifying this tank by the number on your tank lid make sure to carefully measure from center to center of the bolt holes to avoid costly return shipping if you order the incorrect one. Note 2 - American Standard made this tank in both a 1.6 GPF and 1.28 GPF version. They are the same porcelain, with different internal parts. If you purchase this item from us with parts we will set it up to flush 1.6 GPF, and it will work in place of either. The tank you receive may be marked 1.28 or 1.6 inside.