This detector features an advanced sensor for accurate CO detection with a 10-year lifespan. It includes a replaceable lithium battery providing 5 years of continuous protection. The device records peak CO levels on an LCD for easy confirmation of past alarms. The price drops from $29.99 to $17.99 when you apply the coupon code "3MT34N9Y" at checkout. Shipping is free for prime members or on orders over $35.