diff --git a/README.md b/README.md
index 42b61c4..0daef86 100644
--- a/README.md
+++ b/README.md
@@ -93,7 +93,7 @@ Please be aware:
 - 1x M3x18 FHCS (counter sunk screw)
 - 1x M3x8 SHCS
 - 1x M2.5x16 SHCS (15-18mm works)
-- Spring of ballpoint pen (L=15mm; D<=4,5mm) (I've ordered some for testing, to have a "defined" spring)
+- Spring 0.4x4x15 or alternative of ballpoint pen (L=15mm; D<=4,5mm) (I've ordered some for testing, to have a "defined" spring)
 - Type 4 metal hobby blades (we will cut it to length) [Link](https://de.aliexpress.com/item/1005005117830095.html?spm=a2g0o.order_detail.order_detail_item.9.47c26368QwSbBr&gatewayAdapt=glo2deu) Amazon link, these need glue to be held in but work fine (USA) [Link](https://www.amazon.com/dp/B07QP8L1QG)
 - ![Image](https://user-images.githubusercontent.com/83211473/235373488-2253e51a-6892-4dc9-9b53-363d28b1faa8.png)