The string spacing of your S-style guitar indicates which saddle size you need. Therefore, the first step is to identify your string spacing. 

The easiest way to figure this out is by measuring the space between the 2 outer strings of your guitar. Measure at the bridge using a digital caliper.

• If the string spacing is 56 mm (2-7/32 inch), use 11.2 mm (0.441 inch) saddles
• If the string spacing is 54 mm (2-1/8 inch), use 10.8 mm (0.425 inch) saddles
• If the string spacing is 52 mm (2-1/16 inch), use 10.5 mm (0.413 inch) saddles

You can also determine string spacing through the guitar model. Check the serial number on your guitar and search online to find the model.

• Vintage Stratocasters manufactured from the 1950s through the mid-60s have 2-7/32 inch string spacing, and therefore use 11.2 mm (0.441 inch) width saddles. Audible Steel model A112.
• Most contemporary S-style guitars manufactured from the 1980s onward have 2-1/16 inch string spacing, and therefore use 10.5 mm (0.413 inch) width saddles. Audible Steel model A105.
• Some modern “vintage re-issues” have the 2-7/32 inch string spacing, so these also use 11.2 mm (0.441 inch) width saddles. Audible Steel model A112.

NOTE: If your string spacing is just slightly less than 2-7/32 inch, it means your guitar probably has the vintage 11.2 mm sized saddles. However, you will fare better with the 10.8 mm sized saddles. Audible Steel model A108.

The “middle size” saddle for S-style guitars 

Initially there were two standard saddle sizes: vintage and contemporary. A third “middle size” (10.8 mm) emerged over the years which is between the vintage and the contemporary sizes, and is made for 2-1/8 inch string spacing. This size also solves a particular problem with the vintage for 2-7/32 inch string spacing. See our article on this topic for details.