Perfectly fits for Optima battery: for Blue Top 34M, D34M; for Red Top 34, 34/78 (Doesn't fit for 34R); for Yellow Top D34, D34/78 (Doesn't fits for D75 75).
 
The whole outside size of the battery tray is 11.2 x 7.9 inches, adopts embedded design to be perfectly compatible with your Optima.
 
Includes: 6 * Nuts, 6 * 8mm Bolts, 4 * 10mm Bolts, 4 * Bolt Washers, 2 * Fixing Hold-Down Tabs and 1 * Battery Tray.