The Eidolon Hand Held Slit Lamp Model 510L comes with a 5-year guarantee. Repair or replacement of your unit through that period is free. If your guarantee has expired, most units can be rebuilt to current standards and shipped back to you for $200. All of our out-of-guaranty repair work is guaranteed for one year. Damages caused by corroded batteries is considered out-of-guarantee repair work. In the unlikely scenario where the damage to your unit is so extensive that the repair fee would exceed $200, or if a total replacement is required, we will contact you.