Opsmen has many FAST tactical flashlights for various needs. This FAST 302M is designed to be mounted on M-LOK handguards and output 400 lumens. The military-grade 6061-T6 aluminum even has an HAII hard-anodized finish, which itself is military-grade.
You can customize this flashlight to use either a button switch or a pressure switch. The latter lets you keep your off-hand on the handguard at all times. It also conserves battery life since the CR123 batteries last for 1.5 hours continuously.
A layer of anti-scratch coating covers the ultra-clear mineral glass, so you wont experience a defective beam of light.