var explosionRadius = 5.0;
function OnDrawGizmosSelected () {
    // Display the explosion radius when selected
    Gizmos.color = Color.white;
    Gizmos.DrawWireSphere (transform.position, explosionRadius);
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public float explosionRadius = 5.0F;
    void OnDrawGizmosSelected() {
        Gizmos.color = Color.white;
        Gizmos.DrawWireSphere(transform.position, explosionRadius);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public explosionRadius as single = 5.0F

    def OnDrawGizmosSelected():
        Gizmos.color = Color.white
        Gizmos.DrawWireSphere(transform.position, explosionRadius)