Ray Ban Sunglasses. Series Round Double Bridge. Series number: RB3647N. Color code: 906771. Size: 51. Shape: Round. Lens Width: 51 mm. Lens Bridge: 22 mm. Arm Length: 145 mm. 100% UV protection. Non-Polarized. Frame Material: Metal. Frame Color: Light Blue; Bronze-Copper. Lenses Type: Grey Gradient. UPC/EAN code: 8053672834314. Ray Ban Round Double Bridge Grey Gradient Sunglasses RB3647N 906771 51.