diff --git a/notes/3D printing/Filament.md b/notes/3D printing/Filament.md
index ce11b6d..39ebf37 100644
--- a/notes/3D printing/Filament.md	
+++ b/notes/3D printing/Filament.md	
@@ -229,4 +229,23 @@ POM is most commonly used when CNCing plastic.
 - Hydrophobic
 - Most important because of its chemical resistance.
 - Fairly expensive
-- When mildly overheated, turns into horribly toxic chemicals (carbon monoxide, )
\ No newline at end of file
+- When mildly overheated, turns into horribly toxic chemicals (carbon monoxide, hydrogen cyanide, hydrofluoric acid, even more)
+
+# PEEK (Poly-ether Ether Ketone)
+- Mechanical properties massively beyond other plastics
+- Close to steel
+- Twice as tough as the toughest polycarbonate
+- Used in missiles and is fireproof
+- $700 a kilo (at the time of writing)
+- Prints at 400C
+- Requires a 140C heated chamber
+- Extremely high water retention
+- Special bed adhesive required
+- Difficult to print
+
+# PEKK (Polyether Ketone Ketone)
+Same building blocks as PEEK, in different levels
+- Worse than PEEK mechanically, still far beyond other filaments
+- Much easier to print compared to PEEK
+
+# PPS (Polyphenylene Sulphide)
\ No newline at end of file