The numbers on a strip loin spec describe fat trim at the two ends of the cut: 1x1 means one inch of fat left at the flank-side cap and one inch at the sirloin end, and 0x0 means both have been trimmed away completely. That is the whole code, and it applies to both the bone-in strip loin (IMPS 175) and the boneless (IMPS 180).
What each spec buys you
1x1 is the classic foodservice default. The buyer pays for some fat weight but keeps options: trim it back to grind, or leave the cap for searing. 0x0 is the close trim, where the plant has already pulled the cap fat and the tail strip, delivering a portion-ready loin eye. Because the plant ate the yield loss, 0x0 trades at a premium to 1x1, and the premium is the price of not paying freight and labor on fat you were going to remove anyway. That math is why close trims are common in case-ready retail programs and in export specs, where nobody wants to ship fat in a container.
The 0x1 trap
You will also see shorthand like 0x1 or 1x0 on prints and price sheets. Handle these with care: the order convention, which number is the flank end and which is the sirloin end, is not universal, and different houses write it differently. USDA's own purchase option codes pin down 1x1 and 0x0 unambiguously, but a bare 0x1 on a quote can mean more than one thing. The professional move is to confirm which end carries the inch before you compare it against anything. A half-spec is not a spec.
Reading the spread
The 1x1 to 0x0 spread is effectively a quoted price for trim labor and fat yield. When it widens past the cost of doing the trim work yourself, the 1x1 is the buy for anyone with a bench. When it narrows, the close trim is being given away and portion-ready programs should take it. Watching that spread over time tells you more about plant labor and fat credit markets than any single quote does.