Update README.md to include variants section

Removed excerpt and added variants section for clarity.

Author: oscgonfer

docs/Air/SCK2.1/README.md

@@ -8,25 +8,12 @@ field:
   - air
 grade: intermediate
 feature_img: /assets/images/2.1/SCKit_21.png
-excerpt: Measure Indoor or Outdoor Air Quality with this unit. Beyond the metrics from the kit, it can measure CO2 with a very reliable CO2 sensor!
 ---
 
 # {{ name }}
 
 ![]({{feature_img}})
 
-{{ excerpt }}
+## Variants
 
 {{ insert_cards(card_type = "unit", filter = "page_type", value = ['enclosure'])}}
-
-<!--
-- [SCKit](SCK2.1_PMS5003/3D Printed frog box/)
-
-- [SCKit+Co2](SCK2.1_PMS5003_CO2/3D Printed frog box/)
-
-- [SCKit+2EC](SCK2.1_PMS5003_2EC/3D Printed frog box/)
-
-- [SCKit+Co2+HCHO](SCK2.1_PMS5003_CO2_HCHO/3D Printed frog box/)
-
-- [SCKit+2EC+Co2](SCK2.1_PMS5003_2EC_CO2/)
--->