Use this RDO-X Sensor Cap Replacement Kit to replace your expired RDO Cap for Aqua TROLL 400, RDO Pro-X, RDO Blue, or SmarTROLL RDO. The kit contains everything you need, including replacement O-rings to ensure a waterproof seal. Includes a 24-month replacement RDO-X Sensor Cap, lens cloth, silicone O-ring lubricant, replacement O-rings, and an instruction sheet.

See the RDO Cap Explainer for details on RDO Caps.