How do I purchase an Extend ADH Protection Plan? Follow A protection plan can be purchased online through our website. Note that an ADH plan can only be purchased at the time the product is purchased, not after. Related articles How long should I expect my sensors to last? What is an Extend Accidental Damage from Handling (ADH) Protection Plan? How many times can I use the Extend ADH Protection Plan? How do I contact Arccos Support? User Guides in PDF