Technical data: Büchel reflector Z-Flex EVO for attaching to seat posts. Fits all seat posts up to 31.8 mm. Easy to install. *Vertical alignment by ball joint. StVZO approved. Test number: K 1462. Material: Plastic Colour: red. Dimensions (L x W x H): approx. 5.5 x 4 x 8 cm with bracket.... Büchel Z-Flex EVO bicycle reflector seatpost mount universal