About it: The light is GACIRON, the holder is TWTOPSE. The bracket is specially designed for Brompton, Its position is lower and will not affect the luggage bracket. Tips:We update the 400 lumen option to 550 lumen option and the 800 Lumen option to 850 lumen option, the price is same. (the 550,850 option is Blue lens ring, from yellow to blue) Product Details: Brand: GACIRON TWTOPSE Light source: Cree XGP2, Cool Daylight Color Output: 550 Lumen max,850 lumen Mode: 5 modes ( Steady High, Mid, Low; Strobe SOS, Pop ) Control: Top click switch Battery: Built-in lithium polymer battery (2500mAH) Charge: Mirco USB Android port, rated 0.7A 5V, about 3-4 hours to full charge Runtime: 2h30 to 14 hours, subject to light mode in use Casing: Aluminum Alloy #6063, anodized anti-abrasive finish Ingre protection: IPX3, water splash proof. Do not submerge in water for use Features: Sturdy built, #6063 alloy housing, anodized finish ; Cree XPG2 LED chip, cool daylight tone, output up to 400 Lumens; Patterned diffuser for even illumination and direct dazzle reduced; 5 optional light modes to meet cycling needs; Quality circuit ensures stable electric performance; Robust bracket, wide range mount, fits tube dia. 20-40mm; Quick mount / release design. The 550,850 option is Blue lens ring