Flexon COLLINS 600 Eyeglasses 412 Dark Slate Blue 55mm delivers real-world value. Here’s a closer look: Flexon COLLINS 600 Eyeglasses 412 Dark Slate Blue 55mm See photos and details: Flexon COLLINS 600 Eyeglasses 412 Dark Slate Blue 55mm. To get 10% discount use the coupon code VSC10.