You'll need to know all 3 dimensions to find the right one.
Ok, so the length is 1 11/16". Now you need the width (front to back) and the height. Then check your neck to see if you need a flat bottom or a curve that follows the fretboard radius.
The tools to cut your own slots are closer than you think... and free of charge. Use a set of your old roundwound strings as custom-gauge files.
Chop off about a 6" length from each one with a wire cutter and you're in business.
If you've never slotted one before, consider buying an extra in case you screw up the first time. Good luck!
