Marcy Rain Sensor Pad — 44mm with Circle Aperture | MSP2731
✅ In Stock
Marcy MSP2731 rain sensor pad in 44mm with center circle aperture — a specialized silicone interface pad for rain sensor modules that require an open center to accommodate a protruding lens or mounting post. Made from Marcy's fingerprint-resistant silicone using patented clamshell molds that produce a consistently shaped, thicker pad with complete glass contact and no air pockets. The clamshell packaging keeps pads free from contamination until the moment of application. Available in single or 5-pack quantities. Made in the USA.
Specifications
- Part Number: MSP2731
- Size: 44mm outer diameter with circle aperture
- Shape: Round with center opening
- Material: Fingerprint-resistant silicone
- Packaging: Clamshell
- Available Quantities: 1-pack, 5-pack
- Made in: USA
- Application: Rain sensor to windshield optical interface for sensors with protruding lens or mounting post
Application
After windshield installation, position the new pad between the rain sensor lens and the inside glass surface before remounting the sensor. The center aperture accommodates sensors with a protruding central lens or mounting element. Remove from clamshell packaging immediately before application to avoid contamination. Refer to the N. America Interchange Chart or Europe Interchange Chart to confirm this is the correct pad for your vehicle's sensor.
What is the circle aperture and when is it needed?
The circle aperture is an opening in the center of the pad that allows a protruding lens element, optical post, or mounting boss on the rain sensor module to pass through without compressing against the pad. Some rain sensor designs have a raised central element that contacts the glass directly — the aperture pad routes around this element so the pad perimeter creates the optical seal while the center element makes its own contact. The interchange chart identifies which vehicles require an aperture pad.
Why does the rain sensor need a new pad after windshield replacement?
The rain sensor maintains optical contact with the inside surface of the windshield glass to detect water droplets. The silicone pad fills the micro-gap between the sensor lens and the glass, eliminating air (which causes optical interference) and ensuring accurate sensor detection. The original pad bonds to the old glass and cannot be reused — a new pad is required with every windshield replacement.
How do I know which pad size to use?
Pad size is matched to the rain sensor module on the vehicle, not to the windshield itself. Download the Marcy N. America or Europe Interchange Chart (links above) and cross-reference by vehicle year, make, and model to find the correct MSP part number. The interchange chart also indicates whether an aperture pad is required for your specific sensor design.
Why is fingerprint-resistant silicone important?
Standard silicone picks up skin oils and dust during handling, creating micro-voids and optical inconsistencies between the sensor and glass. These voids can cause false rain detection, missed detection, or sensor error codes. Marcy's fingerprint-resistant formula minimizes contamination transfer during application, maintaining a clean, full-contact optical interface.
What is the advantage of clamshell packaging?
Traditional rain sensor pads come in bags where the silicone surface picks up lint and dust during storage. Marcy's clamshell holds the pad in a clean, closed case until the moment of installation. It also eliminates fumbling with a bag when you have urethane on your gloves — open the shell, remove the pad, apply, done.