Durable rubber boot tips for Urban Poling fitness poles (including Series 300, 4Life, Adventure Series) should be replaced when the tread begins to wear to ensure continued grip and shock-absorption. Our exclusive boot tips: Flex on contact to absorb shock and vibration when the poles strike the ground Provide excellent traction on hard surfaces such as sidewalks or pavement Help propel you forward, creating a mechanism to walk faster and achieve a better workout Are quickly and easily removed to expose the carbide tip for walking on softer surfaces such as sand, trails and snow