I carry these polished open ended slides in four main sizes, -
Small - 17.5mm ID - 47.5mm length
Medium - 19.5mm ID - 57.5mm length
Large - 21mm ID - 59mm length
X-Large - 22.5mm ID - 59mm length
Rock Slide slides fit the same across all materials. If a small glass fits you, so will a small ceramic or small brass and on and on. Not all situations and fingers are the same and there is also a degree of personal preference that can’t always be figured out with a measurement. For the majority of customers, pinky finger will take a small slide. Ring finger will take a medium or Large slide. If you have very large hands, medium usually works for the pinky and XL for the ring.
Method 1: Jewelry Store
The most accurate way to size your finger is to stop by your local jeweler and get your ring size which should be free if you ask nicely! and takes about 90 seconds.
Method 2: Measure with Wrenches
If you have access to a set of Metric or USA box wrenches you can very quickly measure your finger. To measure any finger size, use the OPEN END of the wrench. DO NOT use the ring end of the wrench as it could get stuck on your finger. Find the size that slides over the large knuckle snugly like how a ring fits. If it goes over your knuckle without touching the skin then try the next size down.
Need more help gauging the size? Here is a guide from our blog to help you find the right sized slide
How Should a Rock Slide Guitar Slide Fit?
Ideally Rock Slides should fit snug enough that you can point your finger straight down at the ground without the slide falling off. The proper fit is for the slide to stop at the large knuckle creating a 2/3 finger slide. This allows you for bending of the finger with the slide on which makes, playing, fretting and chording much easier.