ChromaKey Shader for Unity

Shader "Custom/ChromaKey" {
    Properties {
        _MainTex ("Base (RGB)", 2D) = "white" {}
    }
    SubShader {
        Tags { "Queue"="Transparent" "RenderType"="Transparent" }
        LOD 200

        CGPROGRAM
        #pragma surface surf Lambert alpha

        sampler2D _MainTex;

        struct Input {
            float2 uv_MainTex;
        };

        void surf (Input IN, inout SurfaceOutput o) {
            half4 c = tex2D (_MainTex, IN.uv_MainTex);
            o.Albedo = c.rgb;

            // #################################
            //
            // CHANGE THESE VALUES DEPENDING ON WHAT SHOULD BE TRANSPARENT
            //
            // #################################
            if (c.g > 200.0/255.0 && c.r < 200.0/255.0 && c.b < 200.0/255.0)
            {
                o.Alpha = 0.0;
            }
            else
            {
                o.Alpha = c.a;
            }
        }
        ENDCG
    }
    FallBack "Diffuse"
}