diff --git a/Mercury_One/README.md b/Mercury_One/README.md
index a25d429..10be8ab 100644
--- a/Mercury_One/README.md
+++ b/Mercury_One/README.md
@@ -51,3 +51,5 @@ like so:
 | DrPeterPlastic | [Wago4-Mount](./DrPeterPlastic/Wago4-Mount-Hydra)  | Mount for 4 Wagos on Hydra | 💚
 | Vengeful | [Klicky Mount](./Vengeful/Klicky_Bracket) | E5 Plus Mounting Bracket for Klicky mod| 💚
 |  | [Standalone Knob Tensioner](./Vengeful/Standalone_Knob_Tensioners) | Knob Tensioners for Mecrury Printers| 💙
+| hrt_plk | [MGN9H gantry](./hrt_plk/gantry-mgn9h) | Custom parts to replace y axis from MGN12 to MGN9 | 💚
+
diff --git a/Mercury_One/hrt_plk/README.md b/Mercury_One/hrt_plk/README.md
new file mode 100644
index 0000000..5209089
--- /dev/null
+++ b/Mercury_One/hrt_plk/README.md
@@ -0,0 +1,4 @@
+## Gantry MGN9H rails
+  - Redesigned from original MGN12H
+  - 4 bolts
+  - successfully assembled
diff --git a/Mercury_One/hrt_plk/stl/gantry-mgn9h/y-l-9.stl b/Mercury_One/hrt_plk/stl/gantry-mgn9h/y-l-9.stl
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diff --git a/Mercury_One/hrt_plk/stl/gantry-mgn9h/y-r-9.stl b/Mercury_One/hrt_plk/stl/gantry-mgn9h/y-r-9.stl
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Binary files /dev/null and b/Mercury_One/hrt_plk/stl/gantry-mgn9h/y-r-9.stl differ