diff --git a/README.md b/README.md
index b42b6df4b9d32ec3679e672bdbe0b0b3c25fafb2..c11a8d4d1e4bc233a8c8fe04f2e6dfe918ea37c6 100644
--- a/README.md
+++ b/README.md
@@ -5,3 +5,7 @@ Masks chatacterized: \
 [Gerson N95](./Gerson_N95/readme.md) \
 [Kimberly-Clark 47117](./KC_47117/readme.md)
 
+
+## Measurement methods
+- filter material width: micrometer, squeezed until width is no longer changing 
+- fiber thickness: SEM, data measurement 
\ No newline at end of file