Width of each finger in millimeters, by size. Measure and compare — you choose your size, no need to send us anything.
SizeThumbIndexMiddleRingPinky
S13mm10mm12mm11mm8mm
M15mm11mm12mm11mm9mm
L18mm14mm16mm14mm12mm
✦
Tip: If you're between two sizes, choose the larger one — it's better to have a little extra room than for it to feel tight. Press-ons shouldn't touch the skin on the sides.