diff --git a/notes/3D printing/Filament.md b/notes/3D printing/Filament.md
index 9caeff6..0ecdbde 100644
--- a/notes/3D printing/Filament.md	
+++ b/notes/3D printing/Filament.md	
@@ -263,4 +263,17 @@ As a general rule, these (CF-PEEK, et cetera), are all extremely difficult to pr
 # PEI (Polyetherimide)
 - Used to coat print beds
 - Sold in two grades, 1010 and 9085 (9085 is horrible and shouldn't be used)
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+- $400/kilo
+- Second strongest filament after PEEK
+- Glass transition temp at 217C
+- Electrically/chemically/radiation resistant
+- Prints at 425C nozzle/160C bed
+- Needs a special bed
+- Relatively friendly to print once equipment requirements are met
+
+# TPI (Thermoplastic Polyamide)
+- Kapton tape, in a filament
+- Glass transition temp above 250C
+- Most heat-proof filament
+- Mechanical properties about 25% worse than PEEK
+- Printing is basically impossible
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