diff --git a/mechanism/README.md b/mechanism/README.md
index 47534e1..a83e010 100644
--- a/mechanism/README.md
+++ b/mechanism/README.md
@@ -1,19 +1,12 @@
# Mechanism
-
-
## Bill of Materials
-### Servo - MG92B
+### Servos
-Servo is the key component. I use TowerPro [MG92B](http://www.towerpro.com.tw/product/mg92b/). It has metal gear (important!).
-An hexapod requires 18 of them.
-
-> The dimension of 3d printed part is highly depended on servo's dimension.
-> Modification is required if you want to use other alternative servo.
-
-> TowerPro MG92B can be found on Ebay seller [servohorns959](https://www.ebay.com/usr/servohorns959), which is listed on TowerPro official website ([Link] (http://www.towerpro.com.tw/about-us-2/)).
I also got mime servo from him.
+18 TowerPro [MG92B](http://www.towerpro.com.tw/product/mg92b/) are required.
+> The dimension of 3d printed part is highly dependent on the servo's size. Modification is required if you want to use alternative servos.
### 3D-Printed Parts
@@ -23,7 +16,6 @@ An hexapod requires 18 of them.
| -------------- | ------------------------------------------- | -------- |
| body_top |  | 1 |
| body_bottom |  | 1 |
-| body_center |  | 1 |
| body_side_wall |  | 2 |
| body_back_wall |  | 1 |