ECSiNG 4X Letterbox Springs with Flex Arms 55x29x13x13.5mm 54x29x13x14.5mm for Traditional Letterbox Letterboards

Size 1: The spring coil has an outer diameter of 7.5 mm, an inner diameter of 5.1 mm, the arm is unfolded 55×29×13×13.5 mm, and the wire diameter is 1.2 mm. Suitable for rods up to 4.5mm diameter (coil diameter decreases as envelope flap opens) Size 2: The coil is more compact, with an outer diameter of 7 mm, an inner diameter of 4.5 mm, an unfolded 54×29×13×14.5 mm, and a wire diameter of 1.2 mm. Suitable for rods up to 4.0mm diameter (coil diameter decreases when opening envelope cover) High-carbon steel wire with surface anti-rust treatment is not easy to deform after repeated opening and closing, and it can return to the position accurately even if there are many letters. Easy to install, no modification is required, directly replace the old spring, so that the mailbox door can open and close smoothly, quietly and labor-saving Mailbox spring with arm, including 2 sizes, convenient for replacement or whole set upgrade., Manufacturer: ECSiNG